builder.circuit is not an instance of a perceval ACircuit

[alexiasalavrakos]

Describe the bug
In the Your First Quantum Layer notebook, at the end, a perceval experiment is based on a circuit obtained with the circuit builder. An error is raised, I believe because the circuit is not an instance of a perceval ACircuit

To Reproduce

from merlin.builder import CircuitBuilder
import perceval as pcvl
builder = CircuitBuilder(n_modes=6)
circuit = builder.circuit
experiment = pcvl.Experiment(circuit)

Observed results
ValueError: The number of modes should be a strictly positive integer (got Circuit(n_modes=6, components=0))

Expected behavior
The last line should run without errors.

Additional context
I then tried

from perceval.components.linear_circuit import Circuit, ACircuit
isinstance(circuit, ACircuit)

I believe the issue comes from there, because of the if loop in perceval's Experiment class, line 134 which calls
if isinstance(m_circuit, ACircuit):

[CassNot]

Hello @alexiasalavrakos,
Thank you for raising this issue !
It should be circuit = builder.to_pcvl_circuit() instead of circuit = builder.circuit
We will update the notebook in the documentation accordingly.