    def test_data_collection_filter_empty(self):
        """
        target: test filter() API for DataCollection 
        method: create an empty data collection and filter it
        expected: return filter successfully
        """
        data = []
        dc = towhee.dc(data)
        dc = dc.filter(str)
        result = dc.to_list()
        assert result == data

        return True
target: test filter() API for DataCollection
method: create an empty data collection and filter it
expected: return filter successfully
tests/testcases/test_data_collection.py