def _dash_escape(args):
    """Escape all elements of 'args' that need escaping.

    'args' may be any sequence and is not modified by this function.
    Return a new list where every element that needs escaping has
    been escaped.

    An element needs escaping when it starts with two ASCII hyphens
    ('--'). Escaping consists in prepending an element composed of
    two ASCII hyphens, i.e., the string '--'.

    """
    res = []

    for arg in args:
        if arg.startswith("--"):
            res.extend(("--", arg))
        else:
            res.append(arg)

    return res