Required functionality.

def ensure_table(self, cls):
        """Required functionality."""
        exists = True
        conn = get_conn()

        try:
            descrip = conn.describe_table(cls.get_table_name())
            assert descrip is not None
        except ResourceNotFoundException:
            # Expected - this is what we get if there is no table
            exists = False
        except JSONResponseError:
            # Also assuming no table
            exists = False

        if not exists:
            table = self.table_schema_call(Table.create, cls)
            assert table is not None