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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 capture_exception(self, error=None):
 # type: (Optional[BaseException]) -> Optional[str] """Captures an exception. The argument passed can be `None` in which case the last exception will be reported, otherwise an exception object or an `exc_info` tuple. """

        client = self.client
        if client is None:
            return None
        if error is None:
            exc_info = sys.exc_info()
        else:
            exc_info = exc_info_from_error(error)

        event, hint = event_from_exception(exc_info, client_options=client.options)
        try:
            return self.capture_event(event, hint=hint)
        except Exception:
            self._capture_internal_exception(sys.exc_info())

        return None