interface ISecurityToken {
    // Standard ERC20 interface
    function symbol() external view returns (string memory);
    function name() external view returns (string memory);
    function decimals() external view returns(uint8);
    function totalSupply() external view returns(uint256);
    function balanceOf(address owner) external view returns(uint256);
    function allowance(address owner, address spender) external view returns(uint256);
    function transfer(address to, uint256 value) external returns(bool);
    function transferFrom(address from, address to, uint256 value) external returns(bool);
    function approve(address spender, uint256 value) external returns(bool);
    function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool);
    function increaseAllowance(address spender, uint256 addedValue) external returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @notice Transfers of securities may fail for a number of reasons. So this function will used to understand the
     * cause of failure by getting the byte value. Which will be the ESC that follows the EIP 1066. ESC can be mapped
     * with a reson string to understand the failure cause, table of Ethereum status code will always reside off-chain
     * @param _to address The address which you want to transfer to
     * @param _value uint256 the amount of tokens to be transferred
     * @param _data The `bytes _data` allows arbitrary data to be submitted alongside the transfer.
     * @return byte Ethereum status code (ESC)
     * @return bytes32 Application specific reason code
     */
    function canTransfer(address _to, uint256 _value, bytes calldata _data) external view returns (byte statusCode, bytes32 reasonCode);

    // Emit at the time when module get added
    event ModuleAdded(
        uint8[] _types,
        bytes32 indexed _name,
        address indexed _moduleFactory,
        address _module,
        uint256 _moduleCost,
        uint256 _budget,
        bytes32 _label,
        bool _archived
    );

    // Emit when the token details get updated
    event UpdateTokenDetails(string _oldDetails, string _newDetails);
    // Emit when the token name get updated
    event UpdateTokenName(string _oldName, string _newName);
    // Emit when the granularity get changed
    event GranularityChanged(uint256 _oldGranularity, uint256 _newGranularity);
    // Emit when is permanently frozen by the issuer
    event FreezeIssuance();
    // Emit when transfers are frozen or unfrozen
    event FreezeTransfers(bool _status);
    // Emit when new checkpoint created
    event CheckpointCreated(uint256 indexed _checkpointId, uint256 _investorLength);
    // Events to log controller actions
    event SetController(address indexed _oldController, address indexed _newController);
    //Event emit when the global treasury wallet address get changed
    event TreasuryWalletChanged(address _oldTreasuryWallet, address _newTreasuryWallet);
    event DisableController();
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    event TokenUpgraded(uint8 _major, uint8 _minor, uint8 _patch);

    // Emit when Module get archived from the securityToken
    event ModuleArchived(uint8[] _types, address _module); //Event emitted by the tokenLib.
    // Emit when Module get unarchived from the securityToken
    event ModuleUnarchived(uint8[] _types, address _module); //Event emitted by the tokenLib.
    // Emit when Module get removed from the securityToken
    event ModuleRemoved(uint8[] _types, address _module); //Event emitted by the tokenLib.
    // Emit when the budget allocated to a module is changed
    event ModuleBudgetChanged(uint8[] _moduleTypes, address _module, uint256 _oldBudget, uint256 _budget); //Event emitted by the tokenLib.

    // Transfer Events
    event TransferByPartition(
        bytes32 indexed _fromPartition,
        address _operator,
        address indexed _from,
        address indexed _to,
        uint256 _value,
        bytes _data,
        bytes _operatorData
    );

    // Operator Events
    event AuthorizedOperator(address indexed operator, address indexed tokenHolder);
    event RevokedOperator(address indexed operator, address indexed tokenHolder);
    event AuthorizedOperatorByPartition(bytes32 indexed partition, address indexed operator, address indexed tokenHolder);
    event RevokedOperatorByPartition(bytes32 indexed partition, address indexed operator, address indexed tokenHolder);

    // Issuance / Redemption Events
    event IssuedByPartition(bytes32 indexed partition, address indexed to, uint256 value, bytes data);
    event RedeemedByPartition(bytes32 indexed partition, address indexed operator, address indexed from, uint256 value, bytes data, bytes operatorData);

    // Document Events
    event DocumentRemoved(bytes32 indexed _name, string _uri, bytes32 _documentHash);
    event DocumentUpdated(bytes32 indexed _name, string _uri, bytes32 _documentHash);

    // Controller Events
    event ControllerTransfer(
        address _controller,
        address indexed _from,
        address indexed _to,
        uint256 _value,
        bytes _data,
        bytes _operatorData
    );

    event ControllerRedemption(
        address _controller,
        address indexed _tokenHolder,
        uint256 _value,
        bytes _data,
        bytes _operatorData
    );

    // Issuance / Redemption Events
    event Issued(address indexed _operator, address indexed _to, uint256 _value, bytes _data);
    event Redeemed(address indexed _operator, address indexed _from, uint256 _value, bytes _data);

    /**
     * @notice Initialization function
     * @dev Expected to be called atomically with the proxy being created, by the owner of the token
     * @dev Can only be called once
     */
    function initialize(address _getterDelegate) external;

    /**
     * @notice The standard provides an on-chain function to determine whether a transfer will succeed,
     * and return details indicating the reason if the transfer is not valid.
     * @param _from The address from whom the tokens get transferred.
     * @param _to The address to which to transfer tokens to.
     * @param _partition The partition from which to transfer tokens
     * @param _value The amount of tokens to transfer from `_partition`
     * @param _data Additional data attached to the transfer of tokens
     * @return ESC (Ethereum Status Code) following the EIP-1066 standard
     * @return Application specific reason codes with additional details
     * @return The partition to which the transferred tokens were allocated for the _to address
     */
    function canTransferByPartition(
        address _from,
        address _to,
        bytes32 _partition,
        uint256 _value,
        bytes calldata _data
    )
        external
        view
        returns (byte statusCode, bytes32 reasonCode, bytes32 partition);

    /**
     * @notice Transfers of securities may fail for a number of reasons. So this function will used to understand the
     * cause of failure by getting the byte value. Which will be the ESC that follows the EIP 1066. ESC can be mapped
     * with a reson string to understand the failure cause, table of Ethereum status code will always reside off-chain
     * @param _from address The address which you want to send tokens from
     * @param _to address The address which you want to transfer to
     * @param _value uint256 the amount of tokens to be transferred
     * @param _data The `bytes _data` allows arbitrary data to be submitted alongside the transfer.
     * @return byte Ethereum status code (ESC)
     * @return bytes32 Application specific reason code
     */
    function canTransferFrom(address _from, address _to, uint256 _value, bytes calldata _data) external view returns (byte statusCode, bytes32 reasonCode);

    /**
     * @notice Used to attach a new document to the contract, or update the URI or hash of an existing attached document
     * @dev Can only be executed by the owner of the contract.
     * @param _name Name of the document. It should be unique always
     * @param _uri Off-chain uri of the document from where it is accessible to investors/advisors to read.
     * @param _documentHash hash (of the contents) of the document.
     */
    function setDocument(bytes32 _name, string calldata _uri, bytes32 _documentHash) external;

    /**
     * @notice Used to remove an existing document from the contract by giving the name of the document.
     * @dev Can only be executed by the owner of the contract.
     * @param _name Name of the document. It should be unique always
     */
    function removeDocument(bytes32 _name) external;

    /**
     * @notice Used to return the details of a document with a known name (`bytes32`).
     * @param _name Name of the document
     * @return string The URI associated with the document.
     * @return bytes32 The hash (of the contents) of the document.
     * @return uint256 the timestamp at which the document was last modified.
     */
    function getDocument(bytes32 _name) external view returns (string memory documentUri, bytes32 documentHash, uint256 documentTime);

    /**
     * @notice Used to retrieve a full list of documents attached to the smart contract.
     * @return bytes32 List of all documents names present in the contract.
     */
    function getAllDocuments() external view returns (bytes32[] memory documentNames);

    /**
     * @notice In order to provide transparency over whether `controllerTransfer` / `controllerRedeem` are useable
     * or not `isControllable` function will be used.
     * @dev If `isControllable` returns `false` then it always return `false` and
     * `controllerTransfer` / `controllerRedeem` will always revert.
     * @return bool `true` when controller address is non-zero otherwise return `false`.
     */
    function isControllable() external view returns (bool controlled);

    /**
     * @notice Checks if an address is a module of certain type
     * @param _module Address to check
     * @param _type type to check against
     */
    function isModule(address _module, uint8 _type) external view returns(bool isValid);

    /**
     * @notice This function must be called to increase the total supply (Corresponds to mint function of ERC20).
     * @dev It only be called by the token issuer or the operator defined by the issuer. ERC1594 doesn't have
     * have the any logic related to operator but its superset ERC1400 have the operator logic and this function
     * is allowed to call by the operator.
     * @param _tokenHolder The account that will receive the created tokens (account should be whitelisted or KYCed).
     * @param _value The amount of tokens need to be issued
     * @param _data The `bytes _data` allows arbitrary data to be submitted alongside the transfer.
     */
    function issue(address _tokenHolder, uint256 _value, bytes calldata _data) external;

    /**
     * @notice issue new tokens and assigns them to the target _tokenHolder.
     * @dev Can only be called by the issuer or STO attached to the token.
     * @param _tokenHolders A list of addresses to whom the minted tokens will be dilivered
     * @param _values A list of number of tokens get minted and transfer to corresponding address of the investor from _tokenHolders[] list
     * @return success
     */
    function issueMulti(address[] calldata _tokenHolders, uint256[] calldata _values) external;

    /**
     * @notice Increases totalSupply and the corresponding amount of the specified owners partition
     * @param _partition The partition to allocate the increase in balance
     * @param _tokenHolder The token holder whose balance should be increased
     * @param _value The amount by which to increase the balance
     * @param _data Additional data attached to the minting of tokens
     */
    function issueByPartition(bytes32 _partition, address _tokenHolder, uint256 _value, bytes calldata _data) external;

    /**
     * @notice Decreases totalSupply and the corresponding amount of the specified partition of msg.sender
     * @param _partition The partition to allocate the decrease in balance
     * @param _value The amount by which to decrease the balance
     * @param _data Additional data attached to the burning of tokens
     */
    function redeemByPartition(bytes32 _partition, uint256 _value, bytes calldata _data) external;

    /**
     * @notice This function redeem an amount of the token of a msg.sender. For doing so msg.sender may incentivize
     * using different ways that could be implemented with in the `redeem` function definition. But those implementations
     * are out of the scope of the ERC1594.
     * @param _value The amount of tokens need to be redeemed
     * @param _data The `bytes _data` it can be used in the token contract to authenticate the redemption.
     */
    function redeem(uint256 _value, bytes calldata _data) external;

    /**
     * @notice This function redeem an amount of the token of a msg.sender. For doing so msg.sender may incentivize
     * using different ways that could be implemented with in the `redeem` function definition. But those implementations
     * are out of the scope of the ERC1594.
     * @dev It is analogy to `transferFrom`
     * @param _tokenHolder The account whose tokens gets redeemed.
     * @param _value The amount of tokens need to be redeemed
     * @param _data The `bytes _data` it can be used in the token contract to authenticate the redemption.
     */
    function redeemFrom(address _tokenHolder, uint256 _value, bytes calldata _data) external;

    /**
     * @notice Decreases totalSupply and the corresponding amount of the specified partition of tokenHolder
     * @dev This function can only be called by the authorised operator.
     * @param _partition The partition to allocate the decrease in balance.
     * @param _tokenHolder The token holder whose balance should be decreased
     * @param _value The amount by which to decrease the balance
     * @param _data Additional data attached to the burning of tokens
     * @param _operatorData Additional data attached to the transfer of tokens by the operator
     */
    function operatorRedeemByPartition(
        bytes32 _partition,
        address _tokenHolder,
        uint256 _value,
        bytes calldata _data,
        bytes calldata _operatorData
    ) external;

    /**
     * @notice Validate permissions with PermissionManager if it exists, If no Permission return false
     * @dev Note that IModule withPerm will allow ST owner all permissions anyway
     * @dev this allows individual modules to override this logic if needed (to not allow ST owner all permissions)
     * @param _delegate address of delegate
     * @param _module address of PermissionManager module
     * @param _perm the permissions
     * @return success
     */
    function checkPermission(address _delegate, address _module, bytes32 _perm) external view returns(bool hasPermission);

    /**
     * @notice Returns module list for a module type
     * @param _module Address of the module
     * @return bytes32 Name
     * @return address Module address
     * @return address Module factory address
     * @return bool Module archived
     * @return uint8 Array of module types
     * @return bytes32 Module label
     */
    function getModule(address _module) external view returns (bytes32 moduleName, address moduleAddress, address factoryAddress, bool isArchived, uint8[] memory moduleTypes, bytes32 moduleLabel);

    /**
     * @notice Returns module list for a module name
     * @param _name Name of the module
     * @return address[] List of modules with this name
     */
    function getModulesByName(bytes32 _name) external view returns(address[] memory modules);

    /**
     * @notice Returns module list for a module type
     * @param _type Type of the module
     * @return address[] List of modules with this type
     */
    function getModulesByType(uint8 _type) external view returns(address[] memory modules);

    /**
     * @notice use to return the global treasury wallet
     */
    function getTreasuryWallet() external view returns(address treasuryWallet);

    /**
     * @notice Queries totalSupply at a specified checkpoint
     * @param _checkpointId Checkpoint ID to query as of
     */
    function totalSupplyAt(uint256 _checkpointId) external view returns(uint256 supply);

    /**
     * @notice Queries balance at a specified checkpoint
     * @param _investor Investor to query balance for
     * @param _checkpointId Checkpoint ID to query as of
     */
    function balanceOfAt(address _investor, uint256 _checkpointId) external view returns(uint256 balance);

    /**
     * @notice Creates a checkpoint that can be used to query historical balances / totalSuppy
     */
    function createCheckpoint() external returns(uint256 checkpointId);

    /**
     * @notice Gets list of times that checkpoints were created
     * @return List of checkpoint times
     */
    function getCheckpointTimes() external view returns(uint256[] memory checkpointTimes);

    /**
     * @notice returns an array of investors
     * NB - this length may differ from investorCount as it contains all investors that ever held tokens
     * @return list of addresses
     */
    function getInvestors() external view returns(address[] memory investors);

    /**
     * @notice returns an array of investors at a given checkpoint
     * NB - this length may differ from investorCount as it contains all investors that ever held tokens
     * @param _checkpointId Checkpoint id at which investor list is to be populated
     * @return list of investors
     */
    function getInvestorsAt(uint256 _checkpointId) external view returns(address[] memory investors);

    /**
     * @notice returns an array of investors with non zero balance at a given checkpoint
     * @param _checkpointId Checkpoint id at which investor list is to be populated
     * @param _start Position of investor to start iteration from
     * @param _end Position of investor to stop iteration at
     * @return list of investors
     */
    function getInvestorsSubsetAt(uint256 _checkpointId, uint256 _start, uint256 _end) external view returns(address[] memory investors);

    /**
     * @notice generates subset of investors
     * NB - can be used in batches if investor list is large
     * @param _start Position of investor to start iteration from
     * @param _end Position of investor to stop iteration at
     * @return list of investors
     */
    function iterateInvestors(uint256 _start, uint256 _end) external view returns(address[] memory investors);

    /**
     * @notice Gets current checkpoint ID
     * @return Id
     */
    function currentCheckpointId() external view returns(uint256 checkpointId);

    /**
     * @notice Determines whether `_operator` is an operator for all partitions of `_tokenHolder`
     * @param _operator The operator to check
     * @param _tokenHolder The token holder to check
     * @return Whether the `_operator` is an operator for all partitions of `_tokenHolder`
     */
    function isOperator(address _operator, address _tokenHolder) external view returns (bool isValid);

    /**
     * @notice Determines whether `_operator` is an operator for a specified partition of `_tokenHolder`
     * @param _partition The partition to check
     * @param _operator The operator to check
     * @param _tokenHolder The token holder to check
     * @return Whether the `_operator` is an operator for a specified partition of `_tokenHolder`
     */
    function isOperatorForPartition(bytes32 _partition, address _operator, address _tokenHolder) external view returns (bool isValid);

    /**
     * @notice Return all partitions
     * @param _tokenHolder Whom balance need to queried
     * @return List of partitions
     */
    function partitionsOf(address _tokenHolder) external view returns (bytes32[] memory partitions);

    /**
     * @notice Gets data store address
     * @return data store address
     */
    function dataStore() external view returns (address dataStoreAddress);

    /**
    * @notice Allows owner to change data store
    * @param _dataStore Address of the token data store
    */
    function changeDataStore(address _dataStore) external;


    /**
     * @notice Allows to change the treasury wallet address
     * @param _wallet Ethereum address of the treasury wallet
     */
    function changeTreasuryWallet(address _wallet) external;

    /**
     * @notice Allows the owner to withdraw unspent POLY stored by them on the ST or any ERC20 token.
     * @dev Owner can transfer POLY to the ST which will be used to pay for modules that require a POLY fee.
     * @param _tokenContract Address of the ERC20Basic compliance token
     * @param _value Amount of POLY to withdraw
     */
    function withdrawERC20(address _tokenContract, uint256 _value) external;

    /**
    * @notice Allows owner to increase/decrease POLY approval of one of the modules
    * @param _module Module address
    * @param _change Change in allowance
    * @param _increase True if budget has to be increased, false if decrease
    */
    function changeModuleBudget(address _module, uint256 _change, bool _increase) external;

    /**
     * @notice Changes the tokenDetails
     * @param _newTokenDetails New token details
     */
    function updateTokenDetails(string calldata _newTokenDetails) external;

    /**
    * @notice Allows owner to change token name
    * @param _name new name of the token
    */
    function changeName(string calldata _name) external;

    /**
    * @notice Allows the owner to change token granularity
    * @param _granularity Granularity level of the token
    */
    function changeGranularity(uint256 _granularity) external;

    /**
     * @notice Freezes all the transfers
     */
    function freezeTransfers() external;

    /**
     * @notice Un-freezes all the transfers
     */
    function unfreezeTransfers() external;

    /**
     * @notice Permanently freeze issuance of this security token.
     * @dev It MUST NOT be possible to increase `totalSuppy` after this function is called.
     */
    function freezeIssuance(bytes calldata _signature) external;

    /**
      * @notice Attachs a module to the SecurityToken
      * @dev  E.G.: On deployment (through the STR) ST gets a TransferManager module attached to it
      * @dev to control restrictions on transfers.
      * @param _moduleFactory is the address of the module factory to be added
      * @param _data is data packed into bytes used to further configure the module (See STO usage)
      * @param _maxCost max amount of POLY willing to pay to the module.
      * @param _budget max amount of ongoing POLY willing to assign to the module.
      * @param _label custom module label.
      * @param _archived whether to add the module as an archived module
      */
    function addModuleWithLabel(
        address _moduleFactory,
        bytes calldata _data,
        uint256 _maxCost,
        uint256 _budget,
        bytes32 _label,
        bool _archived
    ) external;

    /**
     * @notice Function used to attach a module to the security token
     * @dev  E.G.: On deployment (through the STR) ST gets a TransferManager module attached to it
     * @dev to control restrictions on transfers.
     * @dev You are allowed to add a new moduleType if:
     * @dev - there is no existing module of that type yet added
     * @dev - the last member of the module list is replacable
     * @param _moduleFactory is the address of the module factory to be added
     * @param _data is data packed into bytes used to further configure the module (See STO usage)
     * @param _maxCost max amount of POLY willing to pay to module. (WIP)
     * @param _budget max amount of ongoing POLY willing to assign to the module.
     * @param _archived whether to add the module as an archived module
     */
    function addModule(address _moduleFactory, bytes calldata _data, uint256 _maxCost, uint256 _budget, bool _archived) external;

    /**
    * @notice Archives a module attached to the SecurityToken
    * @param _module address of module to archive
    */
    function archiveModule(address _module) external;

    /**
    * @notice Unarchives a module attached to the SecurityToken
    * @param _module address of module to unarchive
    */
    function unarchiveModule(address _module) external;

    /**
    * @notice Removes a module attached to the SecurityToken
    * @param _module address of module to archive
    */
    function removeModule(address _module) external;

    /**
     * @notice Used by the issuer to set the controller addresses
     * @param _controller address of the controller
     */
    function setController(address _controller) external;

    /**
     * @notice This function allows an authorised address to transfer tokens between any two token holders.
     * The transfer must still respect the balances of the token holders (so the transfer must be for at most
     * `balanceOf(_from)` tokens) and potentially also need to respect other transfer restrictions.
     * @dev This function can only be executed by the `controller` address.
     * @param _from Address The address which you want to send tokens from
     * @param _to Address The address which you want to transfer to
     * @param _value uint256 the amount of tokens to be transferred
     * @param _data data to validate the transfer. (It is not used in this reference implementation
     * because use of `_data` parameter is implementation specific).
     * @param _operatorData data attached to the transfer by controller to emit in event. (It is more like a reason string
     * for calling this function (aka force transfer) which provides the transparency on-chain).
     */
    function controllerTransfer(address _from, address _to, uint256 _value, bytes calldata _data, bytes calldata _operatorData) external;

    /**
     * @notice This function allows an authorised address to redeem tokens for any token holder.
     * The redemption must still respect the balances of the token holder (so the redemption must be for at most
     * `balanceOf(_tokenHolder)` tokens) and potentially also need to respect other transfer restrictions.
     * @dev This function can only be executed by the `controller` address.
     * @param _tokenHolder The account whose tokens will be redeemed.
     * @param _value uint256 the amount of tokens need to be redeemed.
     * @param _data data to validate the transfer. (It is not used in this reference implementation
     * because use of `_data` parameter is implementation specific).
     * @param _operatorData data attached to the transfer by controller to emit in event. (It is more like a reason string
     * for calling this function (aka force transfer) which provides the transparency on-chain).
     */
    function controllerRedeem(address _tokenHolder, uint256 _value, bytes calldata _data, bytes calldata _operatorData) external;

    /**
     * @notice Used by the issuer to permanently disable controller functionality
     * @dev enabled via feature switch "disableControllerAllowed"
     */
    function disableController(bytes calldata _signature) external;

    /**
     * @notice Used to get the version of the securityToken
     */
    function getVersion() external view returns(uint8[] memory version);

    /**
     * @notice Gets the investor count
     */
    function getInvestorCount() external view returns(uint256 investorCount);

    /**
     * @notice Gets the holder count (investors with non zero balance)
     */
    function holderCount() external view returns(uint256 count);

    /**
      * @notice Overloaded version of the transfer function
      * @param _to receiver of transfer
      * @param _value value of transfer
      * @param _data data to indicate validation
      * @return bool success
      */
    function transferWithData(address _to, uint256 _value, bytes calldata _data) external;

    /**
      * @notice Overloaded version of the transferFrom function
      * @param _from sender of transfer
      * @param _to receiver of transfer
      * @param _value value of transfer
      * @param _data data to indicate validation
      * @return bool success
      */
    function transferFromWithData(address _from, address _to, uint256 _value, bytes calldata _data) external;

    /**
     * @notice Transfers the ownership of tokens from a specified partition from one address to another address
     * @param _partition The partition from which to transfer tokens
     * @param _to The address to which to transfer tokens to
     * @param _value The amount of tokens to transfer from `_partition`
     * @param _data Additional data attached to the transfer of tokens
     * @return The partition to which the transferred tokens were allocated for the _to address
     */
    function transferByPartition(bytes32 _partition, address _to, uint256 _value, bytes calldata _data) external returns (bytes32 partition);

    /**
     * @notice Get the balance according to the provided partitions
     * @param _partition Partition which differentiate the tokens.
     * @param _tokenHolder Whom balance need to queried
     * @return Amount of tokens as per the given partitions
     */
    function balanceOfByPartition(bytes32 _partition, address _tokenHolder) external view returns(uint256 balance);

    /**
      * @notice Provides the granularity of the token
      * @return uint256
      */
    function granularity() external view returns(uint256 granularityAmount);

    /**
      * @notice Provides the address of the polymathRegistry
      * @return address
      */
    function polymathRegistry() external view returns(address registryAddress);

    /**
    * @notice Upgrades a module attached to the SecurityToken
    * @param _module address of module to archive
    */
    function upgradeModule(address _module) external;

    /**
    * @notice Upgrades security token
    */
    function upgradeToken() external;

    /**
     * @notice A security token issuer can specify that issuance has finished for the token
     * (i.e. no new tokens can be minted or issued).
     * @dev If a token returns FALSE for `isIssuable()` then it MUST always return FALSE in the future.
     * If a token returns FALSE for `isIssuable()` then it MUST never allow additional tokens to be issued.
     * @return bool `true` signifies the minting is allowed. While `false` denotes the end of minting
     */
    function isIssuable() external view returns (bool issuable);

    /**
     * @notice Authorises an operator for all partitions of `msg.sender`.
     * NB - Allowing investors to authorize an investor to be an operator of all partitions
     * but it doesn't mean we operator is allowed to transfer the LOCKED partition values.
     * Logic for this restriction is written in `operatorTransferByPartition()` function.
     * @param _operator An address which is being authorised.
     */
    function authorizeOperator(address _operator) external;

    /**
     * @notice Revokes authorisation of an operator previously given for all partitions of `msg.sender`.
     * NB - Allowing investors to authorize an investor to be an operator of all partitions
     * but it doesn't mean we operator is allowed to transfer the LOCKED partition values.
     * Logic for this restriction is written in `operatorTransferByPartition()` function.
     * @param _operator An address which is being de-authorised
     */
    function revokeOperator(address _operator) external;

    /**
     * @notice Authorises an operator for a given partition of `msg.sender`
     * @param _partition The partition to which the operator is authorised
     * @param _operator An address which is being authorised
     */
    function authorizeOperatorByPartition(bytes32 _partition, address _operator) external;

    /**
     * @notice Revokes authorisation of an operator previously given for a specified partition of `msg.sender`
     * @param _partition The partition to which the operator is de-authorised
     * @param _operator An address which is being de-authorised
     */
    function revokeOperatorByPartition(bytes32 _partition, address _operator) external;

    /**
     * @notice Transfers the ownership of tokens from a specified partition from one address to another address
     * @param _partition The partition from which to transfer tokens.
     * @param _from The address from which to transfer tokens from
     * @param _to The address to which to transfer tokens to
     * @param _value The amount of tokens to transfer from `_partition`
     * @param _data Additional data attached to the transfer of tokens
     * @param _operatorData Additional data attached to the transfer of tokens by the operator
     * @return The partition to which the transferred tokens were allocated for the _to address
     */
    function operatorTransferByPartition(
        bytes32 _partition,
        address _from,
        address _to,
        uint256 _value,
        bytes calldata _data,
        bytes calldata _operatorData
    )
        external
        returns (bytes32 partition);

    /*
    * @notice Returns if transfers are currently frozen or not
    */
    function transfersFrozen() external view returns (bool isFrozen);

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) external;

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() external view returns (bool);

    /**
     * @return the address of the owner.
     */
    function owner() external view returns (address ownerAddress);

    function controller() external view returns(address controllerAddress);

    function moduleRegistry() external view returns(address moduleRegistryAddress);

    function securityTokenRegistry() external view returns(address securityTokenRegistryAddress);

    function polyToken() external view returns(address polyTokenAddress);

    function tokenFactory() external view returns(address tokenFactoryAddress);

    function getterDelegate() external view returns(address delegate);

    function controllerDisabled() external view returns(bool isDisabled);

    function initialized() external view returns(bool isInitialized);

    function tokenDetails() external view returns(string memory details);

    function updateFromRegistry() external;

}
/**
 * @title Interface for all security tokens
 */
function getInvestors() external view returns(address[] memory investors);

/**
 * @notice returns an array of investors
 * NB - this length may differ from investorCount as it contains all investors that ever held tokens
 * @return list of addresses
 */