code: def delete_data_file_attachment(self, identifier, resource_id):
          
          # Get model run to ensure that it exists. If not return False
          model_run = self.get_object(identifier)
          if model_run is None:
              return False
          # Ensure that attachment with given resource identifier exists.
          if not resource_id in model_run.attachments:
              return False
          # Delete file on disk
          os.remove(os.path.join(model_run.attachment_directory, resource_id))
          # Update model run information in the database
          del model_run.attachments[resource_id]
          self.replace_object(model_run)
          return True
docs: Delete attached file with given resource identifier from a mode run.
  
          Raise ValueError if an image archive with the given resource identifier
          is attached to the model run instead of a data file.
  
          Parameters
          ----------
          identifier : string
              Unique model run identifier
          resource_id : string
              Unique attachment identifier
  
          Returns
          -------
          boolean
              True, if file was deleted. False, if no attachment with given
              identifier existed.