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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 get_handler():
 """Return the handler as a named tuple. The named tuple attributes are 'host', 'port', 'signum'. Return None when no handler has been registered. """

    host, port, signum = _pdbhandler._registered()
    if signum:
        return Handler(host if host else DFLT_ADDRESS[0].encode(),
                       port if port else DFLT_ADDRESS[1], signum)