def METHOD_NAME(self, expr):
    eav = {":id": "pk", ":sk1": "19", ":sk2": "21"}
    desired_hash_key, comparison, range_values = parse_expression(
        expression_attribute_values=eav,
        key_condition_expression=expr,
        schema=self.schema,
        expression_attribute_names=dict(),
    )
    assert desired_hash_key == "pk"
    assert comparison == "BETWEEN"
    assert range_values == ["19", "21"]