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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 add_annotation(self, description, **attrs):
 """Add an annotation to span. :type description: str :param description: A user-supplied message describing the event. The maximum length for the description is 256 bytes. :type attrs: kwargs :param attrs: keyworded arguments e.g. failed=True, name='Caching' """

        at = attributes.Attributes(attrs)
        self.add_time_event(time_event_module.TimeEvent(datetime.utcnow(),
                            time_event_module.Annotation(description, at)))