why would python3 recursive function return null - python-3.x

Question

I have this function that when hitting a rate limit will call itself again. It should eventually succeed and return the working data. It works normally then rate limiting works as expected, and finally when the data goes back to normal I get:
TypeError: 'NoneType' object is not subscriptable
def grabPks(pageNum):
# cloudflare blocks bots...use scraper library to get around this or build your own logic to store and use a manually generated cloudflare session cookie... I don't care 😎
req = scraper.get("sumurl.com/"+str(pageNum)).content
if(req == b'Rate Limit Exceeded'):
print("adjust the rate limiting because they're blocking us :(")
manPenalty = napLength * 3
print("manually sleeping for {} seconds".format(manPenalty))
time.sleep(manPenalty)
print("okay let's try again... NOW SERVING {}".format(pageNum))
grabPks(pageNum)
else:
tree = html.fromstring(req)
pk = tree.xpath("/path/small/text()")
resCmpress = tree.xpath("path/a//text()")
resXtend = tree.xpath("[path/td[2]/small/a//text()")
balance = tree.xpath("path/font//text()")
return pk, resCmpress, resXtend, balance
I've tried to move the return to outside of the else scope but then it throws:
UnboundLocalError: local variable 'pk' referenced before assignment

Answer 1

Your top level grabPks doesnt return anything if it is rate limited.
Think about this:
Call grabPks()
You're rate limited so you go into the if statement and call grabPks() again.
This time it succeeds so grabPks() returns the value to the function above it.
The first function now falls out of the if statement, gets to the end of the function and returns nothing.
Try return grabPks(pageNum) instead inside your if block.

Answer 2

well okay... I needed to return grabPKs to make it play nice...:
def grabPks(pageNum):
# cloudflare blocks bots...use scraper library to get around this or build your own logic to store and use a manually generated cloudflare session cookie... I don't care 😎
req = scraper.get("sumurl.com/"+str(pageNum)).content
if(req == b'Rate Limit Exceeded'):
print("adjust the rate limiting because they're blocking us :(")
manPenalty = napLength * 3
print("manually sleeping for {} seconds".format(manPenalty))
time.sleep(manPenalty)
print("okay let's try again... NOW SERVING {}".format(pageNum))
return grabPks(pageNum)
else:
tree = html.fromstring(req)
pk = tree.xpath("/path/small/text()")
resCmpress = tree.xpath("path/a//text()")
resXtend = tree.xpath("[path/td[2]/small/a//text()")
balance = tree.xpath("path/font//text()")
return pk, resCmpress, resXtend, balance