contract Proxy {
  /**
   * @dev Fallback function.
   * Implemented entirely in `_fallback`.
   */
   

  function _implementation(address implementation) internal {
      
  }

  /**
   * @dev Delegates execution to an implementation contract.
   * This is a low level function that doesn't return to its internal call site.
   * It will return to the external caller whatever the implementation returns.
   * @param implementation Address to delegate.
   */
  function _delegate(address implementation) internal {
    
  }
   
}
/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
function _delegate(address implementation) internal {
    
  }
/**
 * @dev Delegates execution to an implementation contract.
 * This is a low level function that doesn't return to its internal call site.
 * It will return to the external caller whatever the implementation returns.
 * @param implementation Address to delegate.
 */