abstract contract InitializableUpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Contract initializer.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  function initialize(address _logic, bytes memory _data) public payable {
    require(_implementation() == address(0));
    assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
    _setImplementation(_logic);
    if(_data.length > 0) {
      (bool success,) = _logic.delegatecall(_data);
      require(success);
    }
  }  
}
/**
 * @title InitializableUpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with an initializer for initializing
 * implementation and init data.
 */
function initialize(address _logic, bytes memory _data) public payable {
  require(_implementation() == address(0));
  assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
  _setImplementation(_logic);
  if(_data.length > 0) {
    (bool success,) = _logic.delegatecall(_data);
    require(success);
  }
}  

/**
 * @dev Contract initializer.
 * @param _logic Address of the initial implementation.
 * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
 * It should include the signature and the parameters of the function to be called, as described in
 * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
 * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
 */