code: def composite_update(self, item, update_dict, soft=False):
          
          return Composite.composite_update(item, update_dict, soft)
docs: Takes a Composite (item) if item is a type that can be converted into a
          Composite then this is done automatically.  Updates all entries it the
          Composite with values from update_dict.  Updates can be soft in which
          case existing values are not overwritten.
  
          A Composite object will be returned.