contract Initializable is AppStorage {
    modifier onlyInit {
        require(initializationBlock == 0);
        _;
    }

    /**
    * @return Block number in which the contract was initialized
    */
    function getInitializationBlock() public view returns (uint256) {
        return initializationBlock;
    }

    /**
    * @dev Function to be called by top level contract after initialization has finished.
    */
    function initialized() internal onlyInit {
        initializationBlock = getBlockNumber();
    }

    /**
    * @dev Returns the current block number.
    *      Using a function rather than `block.number` allows us to easily mock the block number in
    *      tests.
    */
    function getBlockNumber() internal view returns (uint256) {
        return block.number;
    }
}
function initialized() internal onlyInit {
    initializationBlock = getBlockNumber();
}

/**
 * @dev Function to be called by top level contract after initialization has finished.
 */