<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def do_measurement(self, qubit: int) -> int: """ Measure a qubit and collapse the wavefunction :return: The measurement result. A 1 or a 0. """

        if self.rs is None:
            raise ValueError("You have tried to perform a stochastic operation without setting the "
                             "random state of the simulator. Might I suggest using a PyQVM object?")
        measure_0 = lifted_gate_matrix(matrix=P0, qubit_inds=[qubit], n_qubits=self.n_qubits)
        prob_zero = np.trace(measure_0 @ self.density)

        # generate random number to 'roll' for measurement
        if self.rs.uniform() < prob_zero:
            # decohere state using the measure_0 operator
            unitary = measure_0 @ (np.eye(2 ** self.n_qubits) / np.sqrt(prob_zero))
            self.density = unitary.dot(self.density).dot(np.conj(unitary.T))
            return 0
        else:  # measure one
            measure_1 = lifted_gate_matrix(matrix=P1, qubit_inds=[qubit], n_qubits=self.n_qubits)
            unitary = measure_1 @ (np.eye(2 ** self.n_qubits) / np.sqrt(1 - prob_zero))
            self.density = unitary.dot(self.density).dot(np.conj(unitary.T))
            return 1