@classmethod<EOL><INDENT>def arg_signal(cls, parser):<DEDENT>
group = parser.add_argument_group(<EOL>'<STR_LIT>',<EOL>'<STR_LIT>'<EOL>)<EOL>group.add_argument('<STR_LIT>', type=to_hz,<EOL>help='<STR_LIT>')<EOL>group.add_argument('<STR_LIT>', type=to_hz,<EOL>help='<STR_LIT>')<EOL>group.add_argument('<STR_LIT>', type=to_hz, nargs='<STR_LIT:*>',<EOL>help='<STR_LIT>')<EOL>return group<EOL>
Add an `~argparse.ArgumentGroup` for signal-processing options