code: def param_union(*parameterizeds, **kwargs):
      
      warn = kwargs.pop('warn', True)
      if len(kwargs):
          raise TypeError(
              "param_union() got an unexpected keyword argument '{}'".format(
                  kwargs.popitem()[0]))
      d = dict()
      for o in parameterizeds:
          for k in o.param:
              if k != 'name':
                  if k in d and warn:
                      get_logger().warning("overwriting parameter {}".format(k))
                  d[k] = getattr(o, k)
      return d
docs: Given a set of Parameterized objects, returns a dictionary
      with the union of all param name,value pairs across them.
      If warn is True (default), warns if the same parameter has
      been given multiple values; otherwise uses the last value