def initial_mapping(self, circuit: cirq.AbstractCircuit) -> dict[cirq.Qid, cirq.Qid]:
        """Maps the logical qubits of a circuit onto physical qubits on a device.

        Args:
            circuit: the input circuit with logical qubits.

        Returns:
          qubit_map: the initial mapping of logical qubits to physical qubits.
        """
Maps the logical qubits of a circuit onto physical qubits on a device.

        Args:
            circuit: the input circuit with logical qubits.

        Returns:
          qubit_map: the initial mapping of logical qubits to physical qubits.
        
cirq-core/cirq/transformers/routing/initial_mapper.py