code: def make_unique_endings(strings_collection):
      
      res = []
      for i in range(len(strings_collection)):
          # NOTE(msdubov): a trick to handle 'narrow' python installation issues.
          hex_code = hex(consts.String.UNICODE_SPECIAL_SYMBOLS_START+i)
          hex_code = r"\U" + "0" * (8 - len(hex_code) + 2) + hex_code[2:]
          res.append(strings_collection[i] + hex_code.decode("unicode-escape"))
      return res
docs: Make each string in the collection end with a unique character.
      Essential for correct builiding of a generalized annotated suffix tree.
      Returns the updated strings collection, encoded in Unicode.
  
      max strings_collection ~ 1.100.000