__doc__ = u"""

>>> try: exc()

... except IndexError:

...     if IS_PY3:

...         print(isinstance(sys.exc_info()[1].__context__, ValueError))

...     else:

...         print(True)

True

"""

import sys

IS_PY3 = sys.version_info[0] >= 3

def exc():

    try:

        raise ValueError

    except ValueError:

        raise IndexError