Make filters from GET variables.

        :return dict: filters

def get_filters(self, request, **resources):
        """ Make filters from GET variables.

        :return dict: filters

        """
        filters = dict()

        if not self._meta.fields:
            return filters

        for field in request.GET.iterkeys():
            tokens = field.split(LOOKUP_SEP)
            field_name = tokens[0]

            if field_name not in self._meta.fields:
                continue

            exclude = False
            if tokens[-1] == 'not':
                exclude = True
                tokens.pop()

            value = request.GET.getlist(field)
            if len(tokens) == 1:
                value = map(self._meta.model._meta.get_field(field_name).to_python, value)

            if len(value) > 1:
                tokens.append('in')
            else:
                value = value.pop()

            filters[LOOKUP_SEP.join(tokens)] = (value, exclude)

        return filters