def METHOD_NAME(self):
    """
    Invalid input: an eval-able tuple as a string is not proper JSON
    """
    # Create a DatetimeRangeField instance with some params
    daterange = DatetimeRangeField(required=True)
    # The field is supposed to receive JSON, not eval-able python code
    with self.assertRaises(ValidationError) as context:
        daterange.clean('("2018-01-01T06:00:00Z", null)')
    self.assertEqual(context.exception.message, "Invalid JSON formatting")