def at(self, position: int) -> cirq.LineQubit | None:
        """Returns the qubit at the given position, if there is one, else None."""
        q = cirq.LineQubit(position)
        return q if q in self.qubits else None
Returns the qubit at the given position, if there is one, else None.
cirq-aqt/cirq_aqt/aqt_device.py