old_contents: def slices():
      pass
  
new_contents: def slices(s, n):
      m = len(s)
      if n > m:
          raise ValueError("Slice cannot be larger than the string")
      if n < 1:
          raise ValueError("Slices must have a positive non-zero length")
          
      return [list(map(int, s[i:i+n])) for i in range(m-n+1)]
  
subject: Add initial solution