Return a json dictionary representing this model.

def _to_dict(self):
        """Return a json dictionary representing this model."""
        _dict = {}
        if hasattr(self, 'request') and self.request is not None:
            _dict['request'] = self.request._to_dict()
        if hasattr(self, 'response') and self.response is not None:
            _dict['response'] = self.response._to_dict()
        if hasattr(self, 'log_id') and self.log_id is not None:
            _dict['log_id'] = self.log_id
        if hasattr(self,
                   'request_timestamp') and self.request_timestamp is not None:
            _dict['request_timestamp'] = self.request_timestamp
        if hasattr(
                self,
                'response_timestamp') and self.response_timestamp is not None:
            _dict['response_timestamp'] = self.response_timestamp
        if hasattr(self, 'workspace_id') and self.workspace_id is not None:
            _dict['workspace_id'] = self.workspace_id
        if hasattr(self, 'language') and self.language is not None:
            _dict['language'] = self.language
        return _dict