code: def chunk_string(string, length):
      
      return (string[0 + i:length + i] for i in range(0, len(string), length))
docs: Splits a string into fixed-length chunks.
  
      This function returns a generator, using a generator comprehension. The
      generator returns the string sliced, from 0 + a multiple of the length
      of the chunks, to the length of the chunks + a multiple of the length
      of the chunks.
  
      Reference: http://stackoverflow.com/questions/18854620