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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(self, predicate):
 """ Starts tracing with the given callable. Args: predicate (callable that accepts a single :obj:`hunter.Event` argument):
 Return: self """

        self._handler = predicate
        if self.threading_support is None or self.threading_support:
            self._threading_previous = getattr(threading, '_trace_hook', None)
            threading.settrace(self)
        self._previous = sys.gettrace()
        sys.settrace(self)
        return self