def _decompose_entangle(cmd):
    ' Decompose the entangle gate. '
    qr = cmd.qubits[0]
    eng = cmd.engine
    with Control(eng, cmd.control_qubits):
        (H | qr[0])
        with Control(eng, qr[0]):
            (All(X) | qr[1:])
Decompose the entangle gate.
def _decompose_entangle(cmd):
    '  '
    qr = cmd.qubits[0]
    eng = cmd.engine
    with Control(eng, cmd.control_qubits):
        (H | qr[0])
        with Control(eng, qr[0]):
            (All(X) | qr[1:])