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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 logout(self):
 """Explicit Skybell logout."""

        if self.cache(CONST.ACCESS_TOKEN):
            # No explicit logout call as it doesn't seem to matter
            # if a logout happens without registering the app which
            # we aren't currently doing.
            self._session = requests.session()
            self._devices = None

            self.update_cache({CONST.ACCESS_TOKEN: None})

        return True