code: def line_cont_after_delim(ctx, s, line_len=40, delim=(',',),
                            line_cont_token='&'):
      
      last = -1
      s = str(s)
      for i, t in enumerate(s):
          if t in delim:
              if i > line_len:
                  if last == -1:
                      raise ValueError(
                          'No delimiter until already past line_len')
                  i = last
                  return s[:i+1] + line_cont_token + '\n ' + \
                      line_cont_after_delim(
                          ctx, s[i+1:], line_len, delim)
              last = i
      return s
docs: Insert newline (with preceeding `line_cont_token`) afer
      passing over a delimiter after traversing at least `line_len`
      number of characters
  
      Mako convenience function. E.g. fortran does not
      accpet lines of arbitrary length.