def METHOD_NAME():
    class Composite(cirq.Gate):
        def num_qubits(self) -> int:
            return 1
        def _decompose_(self, qubits):
            yield cirq.X(*qubits)
    args = cirq.DensityMatrixSimulationState(
        qubits=cirq.LineQubit.range(1),
        prng=np.random.RandomState(),
        initial_state=0,
        dtype=np.complex64,
    )
    cirq.act_on(Composite(), args, cirq.LineQubit.range(1))
    np.testing.assert_allclose(
        args.target_tensor, cirq.one_hot(index=(1, 1), shape=(2, 2), dtype=np.complex64)
    )