def root_representer(dumper: yaml.Dumper, data: YAMLRoot):
rval = dict()<EOL>for k, v in data.__dict__.items():<EOL><INDENT>if not k.startswith('<STR_LIT:_>') and v is not None and (not isinstance(v, (dict, list)) or v):<EOL><INDENT>rval[k] = v<EOL><DEDENT><DEDENT>return dumper.represent_data(rval)<EOL>
YAML callback -- used to filter out empty values (None, {}, [] and false)

    @param dumper: data dumper
    @param data: data to be dumped
    @return: