def substrings(a, b, n): """Return substrings of length n in both a and b""" global seta global setb x =  y =  for i in range(len(a) - n + 1): x.append(a[i:i+n]) seta = set(x) for i in range(len(b) - n + 1): y.append(b[i:i+n]) setb = set(y) return seta & setb
This is my code for substrings. Error is
handles substring length longer than string length Expected 0 matches, not 1
So I tried using if and while to check whether n is smaller than a and b but they don't work! What am I supposed to do here?