docs: def AsIter(arg):
    """Encapsulates an argument in a tuple, if it's not already iterable."""
    if isinstance(arg, string_types):
      rslt = [arg]
    elif isinstance(arg, collections.Iterable):
      rslt = arg
    elif not arg:
      rslt = []
    else:
      rslt = [arg]
    return tuple(rslt)