Returns field instance and lookup prefix for given attribute name.
        Can be overloaded in subclasses to provide filtering across multiple models.

def get_field_and_lookup(self, name):
        """
        Returns field instance and lookup prefix for given attribute name.
        Can be overloaded in subclasses to provide filtering across multiple models.
        """
        name = self.get_queryset().model._meta.get_field(name)
        lookup_prefix = ''
        return name, lookup_prefix