docs: def Group(params, name=None, type=None):
      """Groups together Params for adding under the 'What' section.
  
      Args:
          params(list of :func:`Param`): Parameter elements to go in this group.
          name(str): Group name. NB ``None`` is valid, since the group may be
              best identified by its type.
          type(str): Type of group, e.g. 'complex' (for real and imaginary).
      """
      atts = {}
      if name:
          atts['name'] = name
      if type:
          atts['type'] = type
      g = objectify.Element('Group', attrib=atts)
      for p in params:
          g.append(p)
      return g