docs: def LookupChain(lookup_func_list):
    """Returns a *function* suitable for passing as the more_formatters argument
    to Template.
  
    NOTE: In Java, this would be implemented using the 'Composite' pattern.  A
    *list* of formatter lookup function behaves the same as a *single* formatter
    lookup funcion.
  
    Note the distinction between formatter *lookup* functions and formatter
    functions here.
    """
    def MoreFormatters(formatter_name):
      for lookup_func in lookup_func_list:
        formatter_func = lookup_func(formatter_name)
        if formatter_func is not None:
          return formatter_func
  
    return MoreFormatters