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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 network(prefix, default_length=24):
 """ Given a prefix, this function returns the corresponding network address. :type prefix: string :param prefix: An IP prefix. :type default_length: long :param default_length: The default ip prefix length. :rtype: string :return: The IP network address. """

    address, pfxlen = parse_prefix(prefix, default_length)
    ip = ip2int(address)
    return int2ip(ip & pfxlen2mask_int(pfxlen))