code: def register(cls, barset, name=None):
          
          return cls_register(cls, barset, BarSet, ('wrapper', ), name=name)
docs: Register a new BarSet as a member/attribute of this class.
              Returns the new BarSet.
              Arguments:
                  barset    : An existing BarSet, or an iterable of strings.
                  name      : New name for the BarSet, also used as the
                              classes attribute name.
                              If the `barset` object has not `name` attribute,
                              this argument is required. It must not be empty
                              when given.