This question applies to both leetcode and real life interviews.

Say we are trying to solve N fibonacci. The starting code will usually be given to us like this:

def getNthFib(n):
	#Write your code here 

If we decide to use the memoization method, where the memo has to get passed into a recursive function, are we allowed to change the original function to this?:

def getNthFib(n, memo={1:0, 2:1}):
	#Write your code here 

Or are you supposed to have the original function call another function? Like this:

def getNthFib(n):
	memo = {1:0, 2:1}
	self.recurseFib(n, memo)
	
def recurseFib(self, n, memo):
	#Write your code here 

I always see people changing the function signature parameters in the discussions for questions. Is this something that you should avoid doing?