code: def append(self, key, value=MARKER, replace=True):
          '''
          Append the item to the metadata.
          '''
          return self.add_item(key, value, replace=replacef append(self, key, value=MARKER, replace=True):
          '''
          Append the item to the metadata.
          '''
          return self.add_item(key, value, replace=replace)
docs: Append the item to the metadata.