code: def is_appendable_to(self, group):
          
          # First check only the names
          if not all([k in group for k in self._entries.keys()]):
              return False
  
          # If names are matching, check the contents
          for k in self._entries.keys():
              if not self._entries[k].is_appendable_to(group):
                  return False
  
          return True
docs: Returns True if the data can be appended in a given group.