def FormatArgList(self, list_node, block_list):
    if block_list == [MTTB]:  # An empty argument list
      return MTTB
    if len(block_list) == 1:  # A singleton list is trivially formatted.
      return block_list[0]
    rhss = [elt.arg.rhs for elt in list_node.elements if elt.arg]
    # In the following, we need to allow for the possibility that the right
    # hand side of an argument list component is empty (i.e. None).
    # TODO(pyelland) Consider returning a ParseNode object of a distinguished
    # class (`EmptyParseNode', for example), rather than None, to signify
    # empty constructs.
    any_braced_arg = _options.force_brace and any(
        r.HasTypeIn(DefaultFormatPolicy.BRACED_CONSTRUCTS) for
        r in rhss if r)
    # Fixed layout for difficult cases, otherwise a WrapBlock. In the latter
    # instance, change the line break penalty to discourage breaking of the
    # parameter list.
    if len(block_list) > DefaultFormatPolicy.MAX_WRAPPED_ARGS or any_braced_arg:
      return SB(block_list)
    return WB(block_list, break_mult=_options.adj_arg)
Test the read functionality.
dataset/ETHPy150Open google/rfmt/formatter/default_format_policy.py/DefaultFormatPolicy.FormatArgList--crossover with--dataset/ETHPy150Open log2timeline/dfvfs/tests/file_io/compressed_stream_io.py/BZIP2CompressedStreamTest.testRead