def validate_fields(self, cls, model):
        " Validate that fields only refer to existing fields, doesn't contain duplicates. "
        # fields
        if cls.fields: # default value is None
            check_isseq(cls, 'fields', cls.fields)
            self.check_field_spec(cls, model, cls.fields, 'fields')
            if cls.fieldsets:
                raise ImproperlyConfigured('Both fieldsets and fields are specified in %s.' % cls.__name__)
            if len(cls.fields) > len(set(cls.fields)):
                raise ImproperlyConfigured(cls.__name__ % 'There are duplicate field(s) in %s.fields')
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/Django-1.6.10/django/contrib/admin/validation.py/BaseValidator.validate_fields/swapped operands of `%`