def _perform_measurement(self, qubits: Sequence[cirq.Qid]) -> list[int]:
        """Delegates the call to measure the `QuantumStateRepresentation`."""
        if self._state is not None:
            return self._state.measure(self.get_axes(qubits), self.prng)
        raise NotImplementedError()
Delegates the call to measure the `QuantumStateRepresentation`.
cirq-core/cirq/sim/simulation_state.py