library AddressUtils {

    /**
    * Returns whether the target address is a contract
    * @dev This function will return false if invoked during the constructor of a contract,
    *  as the code is not actually created until after the constructor finishes.
    * @param addr address to check
    * @return whether the target address is a contract
    */
    function isContract(address addr) internal view returns (bool) {
        uint256 size;
        // XXX Currently there is no better way to check if there is a contract in an address
        // than to check the size of the code at that address.
        // See https://ethereum.stackexchange.com/a/14016/36603
        // for more details about how this works.
        // TODO Check this again before the Serenity release, because all addresses will be
        // contracts then.
        // solium-disable-next-line security/no-inline-assembly
        assembly { size := extcodesize(addr) }
        return size > 0;
    }

}
/**
 * Utility library of inline functions on addresses
 */
function isContract(address addr) internal view returns (bool) {
        uint256 size;
        // XXX Currently there is no better way to check if there is a contract in an address
        // than to check the size of the code at that address.
        // See https://ethereum.stackexchange.com/a/14016/36603
        // for more details about how this works.
        // TODO Check this again before the Serenity release, because all addresses will be
        // contracts then.
        // solium-disable-next-line security/no-inline-assembly
        assembly { size := extcodesize(addr) }
        return size > 0;
    }
/**
 * Returns whether the target address is a contract
 * @dev This function will return false if invoked during the constructor of a contract,
 *  as the code is not actually created until after the constructor finishes.
 * @param addr address to check
 * @return whether the target address is a contract
 */