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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 main():
 """Host a file."""


    description = """Host a file on the LAN."""

    argParser = _argparse.ArgumentParser(description=description)
    argParser.add_argument('file',
                           help='File to host')
    argParser.add_argument('-p', '--port',
                           help='Port to use. (default: 80/8000)',
                           type=int, default=0)

    args = argParser.parse_args()

    absFilePath = _path.abspath(_path.expandvars(_path.expanduser(args.file)))
    if not _path.isfile(absFilePath):
        _sys.stdout.write(u"Couldn't find/access file: " + args.file + "\n")
        _sys.exit(-1)

    tryDefaultPorts = args.port == 0

    # Code from http.server in Python3
    handler = FileHTTPServerHandler
    handler.protocol_version = "HTTP/1.0"
    handler.absFilePath = absFilePath

    port = 80 if tryDefaultPorts else args.port

    try:
        server_address = ("", port)
        httpd = _B.HTTPServer(server_address, handler)
    except IOError as e:
        # If it is a permission denied error, and we had been ambitiously
        # trying port, 80, let's try port 8000 instead
        if e.errno == 13 and tryDefaultPorts:
            port = 8000
            server_address = ("", port)
            httpd = _B.HTTPServer(server_address, handler)
        else:
            raise

    sa = httpd.socket.getsockname()
    _sys.stderr.write("Serving file {} on {}:{} ...\n"
                        .format(absFilePath, sa[0], sa[1]))

    possibleIps = getValidIPs()
    if len(possibleIps) == 0:
        _sys.stderr.write(u'No IPs for localhost found. ' +
                          u'Are you connected to LAN?\n')
    else:
        _sys.stderr.write(u'Download the file by pointing the browser ' +
                          u'on the remote machine to:\n')
        portStr = '' if port == 80 else ':' + str(port)
        for ip in possibleIps:
            _sys.stderr.write(u'\t' + ip + portStr + '\n')

    _sys.stderr.write('Press Ctrl-C to stop hosting.\n')

    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        _sys.stderr.write("\nKeyboard interrupt received, exiting.\n")
        httpd.server_close()
        _sys.exit(0)