<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _rec_get_names(args, names=None):
 """return a list of all argument names"""

    if names is None:
        names = []
    for arg in args:
        if isinstance(arg, node_classes.Tuple):
            _rec_get_names(arg.elts, names)
        else:
            names.append(arg.name)
    return names