code: def _add_gmaf(self, variant_obj, gemini_variant):
          
          max_af = gemini_variant['max_aaf_all']
          if max_af:
              max_af = float(max_af)
              if max_af != -1.0:
                  variant_obj.set_max_freq(max_af)
docs: Add the gmaf frequency
          
          Args:
              variant_obj (puzzle.models.Variant)
              gemini_variant (GeminiQueryRow)