code: def extend(self, items, replace=True):
          '''
          Append the items to the metadata.
          '''
          if isinstance(items, dict) or isinstance(items, SortableDict):
              items = list(items.items())
  
          for (key, value) in items:
              self.append(key, value, replace=replacef extend(self, items, replace=True):
          '''
          Append the items to the metadata.
          '''
          if isinstance(items, dict) or isinstance(items, SortableDict):
              items = list(items.items())
  
          for (key, value) in items:
              self.append(key, value, replace=replace)
docs: Append the items to the metadata.