new_contents: from itertools import zip_longest as zlo
  import re
  
  def solve(s):
      c = sorted(re.findall('[^aeiou]', s))
      v = sorted(re.findall('[aeiou]', s))
      if abs(len(c)-len(v))>1: return 'failed'
      return ''.join(i+j if len(c)<=len(v) else j+i for i,j in zlo(v,c, fillvalue=''))
  
subject: Create 6kyu_vowel-consonant_lexicon.py