class_docstr: Scansion constants can be modified and passed into the constructor if desired.
docstr: Find clusters of consonants that do not contain a vowel.
  :param letters:
  :return:
docstr_tok: ["Find","clusters","of","consonants","that","do","not","contain","a","vowel",".",":","param","letters",":",":","return",":"]
code: def _find_consonant_cluster(self, letters: List[str]) -> List[int]:
      """
      Find clusters of consonants that do not contain a vowel.
      :param letters:
      :return:
      """
      for idx, letter_group in enumerate(letters):
          if self._contains_consonants(
              letter_group
          ) and not self._contains_vowels(letter_group):
              return [idx]
      return []
  
imports: import copy
  import logging
  import re
  from typing import List
  import cltk.prosody.lat.string_utils
  from cltk.prosody.lat.scansion_constants import ScansionConstants
label_desc: Use image node_id 13 for calling the Syllabifier obj's underlying member method code with example usage: obj._find_consonant_cluster(letters) and returns: list, list