from qiskit import QuantumCircuit
from qiskit.quantum_info import Statevector
qc = QuantumCircuit(2)
qc.h([0, 1])       # equal amplitudes over four candidates
qc.cz(0, 1)       # mark |11> by changing its phase
qc.h([0, 1]); qc.x([0, 1])
qc.cz(0, 1)       # reflection about the uniform state (up to global phase)
qc.x([0, 1]); qc.h([0, 1])
print(qc.draw())
print(Statevector.from_instruction(qc).probabilities_dict())
# Expected: {'11': 1.0}