def __getitem__(self, key):
        """
        use ``[]`` indexing notation as a short form for expression repetition:
         - ``expr[n]`` is equivalent to ``expr*n``
         - ``expr[m, n]`` is equivalent to ``expr*(m, n)``
         - ``expr[n, ...]`` or ``expr[n,]`` is equivalent
              to ``expr*n + ZeroOrMore(expr)``
              (read as "at least n instances of ``expr``")
         - ``expr[..., n]`` is equivalent to ``expr*(0, n)``
              (read as "0 to n instances of ``expr``")
         - ``expr[...]`` and ``expr[0, ...]`` are equivalent to ``ZeroOrMore(expr)``
         - ``expr[1, ...]`` is equivalent to ``OneOrMore(expr)``
         ``None`` may be used in place of ``...``.

        Note that ``expr[..., n]`` and ``expr[m, n]``do not raise an exception
        if more than ``n`` ``expr``s exist in the input stream.  If this behavior is
        desired, then write ``expr[..., n] + ~expr``.
       """

        # convert single arg keys to tuples
        try:
            if isinstance(key, str):
                key = (key,)
            iter(key)
        except TypeError:
            key = (key, key)

        if len(key) > 2:
            warnings.warn("only 1 or 2 index arguments supported ({0}{1})".format(key[:5],
                                                                                '... [{0}]'.format(len(key))
                                                                                if len(key) > 5 else ''))

        # clip to 2 elements
        ret = self * tuple(key[:2])
        return ret

        use ``[]`` indexing notation as a short form for expression repetition:
         - ``expr[n]`` is equivalent to ``expr*n``
         - ``expr[m, n]`` is equivalent to ``expr*(m, n)``
         - ``expr[n, ...]`` or ``expr[n,]`` is equivalent
              to ``expr*n + ZeroOrMore(expr)``
              (read as "at least n instances of ``expr``")
         - ``expr[..., n]`` is equivalent to ``expr*(0, n)``
              (read as "0 to n instances of ``expr``")
         - ``expr[...]`` and ``expr[0, ...]`` are equivalent to ``ZeroOrMore(expr)``
         - ``expr[1, ...]`` is equivalent to ``OneOrMore(expr)``
         ``None`` may be used in place of ``...``.

        Note that ``expr[..., n]`` and ``expr[m, n]``do not raise an exception
        if more than ``n`` ``expr``s exist in the input stream.  If this behavior is
        desired, then write ``expr[..., n] + ~expr``.
       
product/gradle-plugin/src/main/python/pip/_vendor/pyparsing.py