original_string: public function authenticate()
      {
          $result = call_user_func_array($this->_callback, $this->_params);
          if ( !($result instanceof Result)) {
              if ($result === true) {
                  $result = new Result(Result::SUCCESS, $this->_identity);
              } else {
                  $result = new Result(Result::FAILURE_CREDENTIAL_INVALID, $this->_identity);
              }
          }
          return $result;
      }
code: public function authenticate()
      {
          $result = call_user_func_array($this->_callback, $this->_params);
          if ( !($result instanceof Result)) {
              if ($result === true) {
                  $result = new Result(Result::SUCCESS, $this->_identity);
              } else {
                  $result = new Result(Result::FAILURE_CREDENTIAL_INVALID, $this->_identity);
              }
          }
          return $result;
      }
code_tokens: public function authenticate ( ) { $ result = call_user_func_array ( $ this -> _callback , $ this -> _params ) ; if ( ! ( $ result instanceof Result ) ) { if ( $ result === true ) { $ result = new Result ( Result :: SUCCESS , $ this -> _identity ) ; } else { $ result = new Result ( Result :: FAILURE_CREDENTIAL_INVALID , $ this -> _identity ) ; } } return $ result ; }
docstring: Perform the authenticate attempt
  
  @return Result
docstring_tokens: Perform the authenticate attempt