code: def run_field_processor(self, field_data):
          
          if field_data.name.endswith("_speed"):
              self.process_field_speed(field_data)
          else:
              super(StandardUnitsDataProcessor, self).run_field_processor(field_data)
docs: Convert all '*_speed' fields using 'process_field_speed'
          All other units will use the default method.