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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 prefixlen_to_mask(prefixlen):
 """Converts a prefix length to a dotted decimal subnet mask Args: prefixlen (str):
 The prefix length value to convert Returns: str: The subt mask as a dotted decimal string """

    prefixlen = prefixlen or '32'
    addr = '0.0.0.0/%s' % prefixlen
    return str(netaddr.IPNetwork(addr).netmask)