how to use variable from another function in python

>>> def oneFunction(lists):
        category=random.choice(list(lists.keys()))
        return random.choice(lists[category])


>>> def anotherFunction():
        for letter in oneFunction(lists):              
        print("_",end=" ")

class Spam:
    def oneFunction(self,lists):
        category=random.choice(list(lists.keys()))
        self.word=random.choice(lists[category])

    def anotherFunction(self):
        for letter in self.word:              
        print("_",end=" ")

s = Spam()
s.oneFunction(lists)
s.anotherFunction()