PennyLane commit breaking the plugin

[nvitucci]

I noticed that a recent commit in PennyLane introduced a bug in the master version of the plugin, resulting in a KeyError: <Wires = [0]> exception when the circuit is evaluated. Minimal example:

1. Install PennyLane with pip
2. Clone this repo and install it with pip install -e .
3. Run this code:

import pennylane as qml

def circuit(angles, **kwargs):
    qml.RX(angles[0], wires=0)
    
dev = qml.device('forest.qvm', device='2q-qvm', shots=10, noisy=True)

params = [0.2]
qnode = qml.map(circuit, [qml.PauliZ(0)], dev)
print(qnode(params))

[josh146]

Thanks @nvitucci! We're in the process of adding a new wires class to PennyLane, and were attempting to add it in a non-breaking manner - looks like that hasn't worked 🙂

We'll have a think back over in PennyLane core and decide the best way to fix this

[antalszava]

Closing this after it has been resolved with updates such as #55.