Write a recursive function named is_subsequence that takes two string parameters and returns True if the first string is a subsequence of the second string, but returns False otherwise. We say that string A is a subsequence of string B if you can derive A by deleting zero or more letters from B without changing the order of the remaining letters. You can assume that neither string contains upper-case letters. You may use default arguments and/or helper functions.
Your recursive function must not: use imports. use any loops use any variables declared outside of the function. use any mutable default arguments.
What I have so far (must use this format):
def is_subsequence(strA, strB = None):
if strB == None:
strB = []
print(is_subsequence("dog", "dodger"))
My problem:
I can't figure out how to recursively edit the string the way the assignment says by removing letters. (strB. replace("e","") doesn't work) or how to do this without passing an index.