r"""
:Author:    Franz Glasner
:Copyright: (c) 2020 Franz Glasner.
            All rights reserved.
:License:   BSD 3-Clause "New" or "Revised" License.
            See :ref:`LICENSE <license>` for details.
            If you cannot find LICENSE see
            <https://opensource.org/licenses/BSD-3-Clause>
:ID:        @(#) HGid$

"""


import argparse
import hashlib
import sys


def main(argv=None):

    aparser = argparse.ArgumentParser(
        description="Python implementation of shasum",
        fromfile_prefix_chars='@')

    opts = aparser.parse_args(args=argv)


def compute_digest(hashobj, instream):
    """

    :param hashobj: a :mod:`hashlib` compatible hash algorithm instance
    :param instream: a bytes input stream to read the data to be hashed from
    :return: the digest in hex form
    :rtype: str

    """
    
if __name__ == "__main__":
    sys.exit(main())