code: def unique_field_data_types(self):
          
          data_type_names = set()
          for field in self.fields:
              if not is_void_type(field.data_type):
                  if field.data_type.name in data_type_names:
                      return False
                  else:
                      data_type_names.add(field.data_type.name)
          else:
              return True
docs: Checks if all variants have different data types.
  
          If so, the selected variant can be determined just by the data type of
          the value without needing a field name / tag. In some languages, this
          lets us make a shortcut