symmetric difference not accepted in normal mode

[fbouchet]

Although accepted in Python101 (according to the reference sheet), the symmetric difference (^) currently raises a warning in normal mode.
For instance, the MWE below:

def sym_diff(e1,e2):
    """set[alpha]**2 -> set[alpha]"""
    return e1^e2

raises the following error:
==> Non-Python101: cette construction n'est pas disponible en Python101 (vous pouvez essayer le mode expert pour faire du Python standard)
BinOp(left=Name(id='e1', ctx=Load()), op=BitXor(), right=Name(id='e2', ctx=Load()))

[fredokun]

Well, need to take action here... Maybe remove from the reference sheet by lack of practical use in the course ? Or otherwise support it ...