In trying to upgrade code from Python 2 to 3, the below code broke for a calculate field that functioned in 2.x. I tried putting double quotes around the (' & ') based on some searching, but did not do the trick.
!FullName!.split(' & ')[1].split('/')[0]
The error is:
ERROR 000539: Traceback (most recent call last):
File "<expression>", line 1, in <module>
IndexError: list index out of range
Failed to execute (Calculate Field (4)).