Rockstar-py fails concat number and string

[tobiasheineken]

Rockstar-py seems not to be able to compile 99-beer.rock (from rockstar/examples):

python3 -W ignore -m rockstarpy --output bottles.py --input $ROCKSTAR/examples/99_beers.rock

runs fine, but

python3 bottles.py 
Traceback (most recent call last):
  File "bottles.py", line 6, in <module>
    print(the_beers + your_heart)
TypeError: unsupported operand type(s) for +: 'int' and 'str'