library Address {
	/**
	 * @dev Returns true if `account` is 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.
	 *
	 * Among others, `isContract` will return false for the following 
	 * types of addresses:
	 *
	 *  - an externally-owned account
	 *  - a contract in construction
	 *  - an address where a contract will be created
	 *  - an address where a contract lived, but was destroyed
	 * ====
	 */
	function isContract(address account) internal view returns (bool) {
		// 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 != accountHash && codehash != 0x0);
	}

	/**
	 * @dev Converts an `address` into `address payable`. Note that this is
	 * simply a type cast: the actual underlying value is not changed.
	 *
	 * _Available since v2.4.0._
	 */
	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].
	 *
	 * _Available since v2.4.0._
	 */
	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 toPayable(address account) internal pure returns (address payable) {
		return address(uint160(account));
	}
/**
 	 * @dev Converts an `address` into `address payable`. Note that this is
 	 * simply a type cast: the actual underlying value is not changed.
 	 *
 	 * _Available since v2.4.0._
 	 */