library Address {
   /**
    * @dev Returns true if `account` is a contract.
    *
    * This test is non-exhaustive, and there may be false-negatives: during the
    * execution of a contract's constructor, its address will be reported as
    * not containing a contract.
    *
    * IMPORTANT: It is unsafe to assume that an address for which this
    * function returns false is an externally-owned account (EOA) and not a
    * contract.
    */
   function isContract(address account) internal view returns (bool) {
       // This method relies in extcodesize, which returns 0 for contracts in
       // construction, since the code is only stored at the end of the
       // constructor execution.

       // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
       // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
       // for accounts without code, i.e. `keccak256('')`
       bytes32 codehash;
       bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
       // solhint-disable-next-line no-inline-assembly
       assembly { codehash := extcodehash(account) }
       return (codehash != 0x0 && codehash != accountHash);
   }

   /**
    * @dev Converts an `address` into `address payable`. Note that this is
    * simply a type cast: the actual underlying value is not changed.
    *
    * NOTE: This is a feature of the next version of OpenZeppelin Contracts.
    * @dev Get it via `npm install @openzeppelin/contracts@next`.
    */
   function toPayable(address account) internal pure returns (address payable) {
       return address(uint160(account));
   }

   /**
    * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
    * `recipient`, forwarding all available gas and reverting on errors.
    *
    * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
    * of certain opcodes, possibly making contracts go over the 2300 gas limit
    * imposed by `transfer`, making them unable to receive funds via
    * `transfer`. {sendValue} removes this limitation.
    *
    * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
    *
    * IMPORTANT: because control is transferred to `recipient`, care must be
    * taken to not create reentrancy vulnerabilities. Consider using
    * {ReentrancyGuard} or the
    * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
    */
   function sendValue(address payable recipient, uint256 amount) internal {
       require(address(this).balance >= amount, "Address: insufficient balance");

       // solhint-disable-next-line avoid-call-value
       (bool success, ) = recipient.call.value(amount)("");
       require(success, "Address: unable to send value, recipient may have reverted");
   }
}
/**
 * @dev Collection of functions related to the address type
 */
function sendValue(address payable recipient, uint256 amount) internal {
    require(address(this).balance >= amount, "Address: insufficient balance");

    // solhint-disable-next-line avoid-call-value
    (bool success, ) = recipient.call.value(amount)("");
    require(success, "Address: unable to send value, recipient may have reverted");
}

/**
 * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
 * `recipient`, forwarding all available gas and reverting on errors.
 *
 * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
 * of certain opcodes, possibly making contracts go over the 2300 gas limit
 * imposed by `transfer`, making them unable to receive funds via
 * `transfer`. {sendValue} removes this limitation.
 *
 * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
 *
 * IMPORTANT: because control is transferred to `recipient`, care must be
 * taken to not create reentrancy vulnerabilities. Consider using
 * {ReentrancyGuard} or the
 * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
 */