Takes a sql alchemy column object and adds label info if supported by engine.
        :param sqla_col: sql alchemy column instance
        :param label: alias/label that column is expected to have
        :return: either a sql alchemy column or label instance if supported by engine

def make_sqla_column_compatible(self, sqla_col, label=None):
        """Takes a sql alchemy column object and adds label info if supported by engine.
        :param sqla_col: sql alchemy column instance
        :param label: alias/label that column is expected to have
        :return: either a sql alchemy column or label instance if supported by engine
        """
        label_expected = label or sqla_col.name
        db_engine_spec = self.database.db_engine_spec
        if db_engine_spec.supports_column_aliases:
            label = db_engine_spec.make_label_compatible(label_expected)
            sqla_col = sqla_col.label(label)
        sqla_col._df_label_expected = label_expected
        return sqla_col