code: def _ensure_regexp(source, n):  #<- this function has to be improved
      '''returns True if regexp starts at n else returns False
        checks whether it is not a division '''
      markers = '(+~"\'=[%:?!*^|&-,;/\\'
      k = 0
      while True:
          k += 1
          if n - k < 0:
              return True
          char = source[n - k]
          if char in markers:
              return True
          if char != ' ' and char != '\n':
              break
      return Falsf _ensure_regexp(source, n):  #<- this function has to be improved
      '''returns True if regexp starts at n else returns False
        checks whether it is not a division '''
      markers = '(+~"\'=[%:?!*^|&-,;/\\'
      k = 0
      while True:
          k += 1
          if n - k < 0:
              return True
          char = source[n - k]
          if char in markers:
              return True
          if char != ' ' and char != '\n':
              break
      return False
docs: returns True if regexp starts at n else returns False
        checks whether it is not a division