code: def _prepare_filtering_params(domain=None, category=None, 
                                    sponsored_source=None, has_field=None,
                                    has_fields=None, query_params_match=None, 
                                    query_person_match=None, **kwargs):
          
          if query_params_match not in (None, True):
              raise ValueError('query_params_match can only be `True`')
          if query_person_match not in (None, True):
              raise ValueError('query_person_match can only be `True`')
          
          params = []
          if domain is not None:
              params.append('domain:%s' % domain)
          if category is not None:
              Source.validate_categories([category])
              params.append('category:%s' % category)
          if sponsored_source is not None:
              params.append('sponsored_source:%s' % sponsored_source)
          if query_params_match is not None:
              params.append('query_params_match')
          if query_person_match is not None:
              params.append('query_person_match')
          has_fields = has_fields or []
          if has_field is not None:
              has_fields.append(has_field)
          for has_field in has_fields:
              params.append('has_field:%s' % has_field.__name__)
          return params
docs: Transform the params to the API format, return a list of params.