code: def create(self, document_data):
          
          batch = self._client.batch()
          batch.create(self, document_data)
          write_results = batch.commit()
          return _first_write_result(write_results)
docs: Create the current document in the Firestore database.
  
          Args:
              document_data (dict): Property names and values to use for
                  creating a document.
  
          Returns:
              google.cloud.firestore_v1beta1.types.WriteResult: The
              write result corresponding to the committed document. A write
              result contains an ``update_time`` field.
  
          Raises:
              ~google.cloud.exceptions.Conflict: If the document already exists.