`pennylane.qnodes.base.QuantumFunctionError: Continuous and discrete operations are not allowed in the same quantum circuit.`

Here is the code (its a modification to mixer and phase ccts for your qaoa maxcut tutorial):

```
def Um(beta):
for i, edge in enumerate(Eo):
t = edge[0]
c = edge[1]
for j in c:
qml.X(wires=j)
if len(c) > 1:
qml.Toffoli(wires=c+[n - 1])
else:
qml.CNOT(wires=c+[n - 1])
qml.CRX(2*beta, wires=[n - 1, t])
for j in c:
qml.X(wires=j)
if len(c) > 1:
qml.Toffoli(wires=c+[n - 1])
else:
qml.CNOT(wires=c+[n - 1])
def Up(gamma):
for i in range(n):
qml.RZ(-gamma, wires=i)
```

I am suspicious of the toffoli gate since its not mentioned as an operation in the discrete docs explicitly. However I know its a standard qubit type operator. Let me know if perhaps you need the full code.