code: def join_syllables_spaces(syllables: List[str], spaces: List[int]) -> str:
      
      syllable_line = list("".join(syllables))
      for space in spaces:
          syllable_line.insert(space, " ")
      return "".join(flatten(syllable_line))
docs: Given a list of syllables, and a list of integers indicating the position of spaces, return
      a string that has a space inserted at the designated points.
  
      :param syllables:
      :param spaces:
      :return:
  
      >>> join_syllables_spaces(["won", "to", "tree", "dun"], [3, 6, 11])
      'won to tree dun'