code: def _record_from_json(value, field):
      
      if _not_null(value, field):
          record = {}
          record_iter = zip(field.fields, value["f"])
          for subfield, cell in record_iter:
              converter = _CELLDATA_FROM_JSON[subfield.field_type]
              if subfield.mode == "REPEATED":
                  value = [converter(item["v"], subfield) for item in cell["v"]]
              else:
                  value = converter(cell["v"], subfield)
              record[subfield.name] = value
          return record
docs: Coerce 'value' to a mapping, if set or not nullable.