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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 _trace_handler(publisher, value, label=None):
 """ Default trace handler is printing the timestamp, the publisher name and the emitted value """

        line = '--- %8.3f: ' % (time() - Trace._timestamp_start)
        line += repr(publisher) if label is None else label
        line += ' %r' % (value,)
        print(line)