When using Python3 with missing PyYAML package, the following line of code is executed:

print (e + " To install it, type:")

however, the print fails as there's a type mismatch between variable e and the string that follows.

The following change is proposed as fix:
change code from

print (e + " To install it, type:")

to:

print (str(e) + " To install it, type:")