Load dataframe based on specified connection
        :return:

def _get_dataframe(self):
        """
        Load dataframe based on specified connection
        :return:
        """
        if self.source_conn is None:  # Use local file
            return ge.read_csv(self.dataset_name, **self.dataset_params)

        if isinstance(self.source_conn, S3Hook):
            hook = ExpectationS3CsvHook(aws_conn_id=self.source_conn_id)

            return hook.get_ge_df(self.dataset_name, self.source_bucket_name, **self.dataset_params)

        if isinstance(self.source_conn, DbApiHook):
            hook = ExpectationMySQLHook(mysql_conn_id=self.source_conn_id)

            return hook.get_ge_df(self.dataset_name, **self.dataset_params)