How to use the pypistats._filter function in pypistats

def test__filter_start_and_end_date(self):
        # Arrange
        data = copy.deepcopy(PYTHON_MINOR_DATA)
        start_date = "2018-09-01"
        end_date = "2018-09-11"

        # Act
        output = pypistats._filter(data, start_date=start_date, end_date=end_date)

        # Assert
        self.assertEqual(len(output), 112)
        for row in output:
            self.assertGreaterEqual(row["date"], start_date)
            self.assertLessEqual(row["date"], end_date)

def test__filter_start_date(self):
        # Arrange
        data = copy.deepcopy(PYTHON_MINOR_DATA)
        start_date = "2018-09-22"

        # Act
        output = pypistats._filter(data, start_date=start_date)

        # Assert
        self.assertEqual(len(output), 20)
        for row in output:
            self.assertGreaterEqual(row["date"], start_date)

def test__filter_no_filters_no_change(self):
        # Arrange
        data = copy.deepcopy(PYTHON_MINOR_DATA)

        # Act
        output = pypistats._filter(data)

        # Assert
        self.assertEqual(data, output)

def test__filter_end_date(self):
        # Arrange
        data = copy.deepcopy(PYTHON_MINOR_DATA)
        end_date = "2018-04-22"

        # Act
        output = pypistats._filter(data, end_date=end_date)

        # Assert
        self.assertEqual(len(output), 62)
        for row in output:
            self.assertLessEqual(row["date"], end_date)