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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def do_create(marfile, files, compress, productversion=None, channel=None, signing_key=None, signing_algorithm=None):
 """Create a new MAR file."""

    with open(marfile, 'w+b') as f:
        with MarWriter(f, productversion=productversion, channel=channel,
                       signing_key=signing_key,
                       signing_algorithm=signing_algorithm,
                       ) as m:
            for f in files:
                m.add(f, compress=compress)