code: def coleman_liau_index(doc: Doc) -> float:
      """
      Readability test whose value estimates the number of years of education
      required to understand a text, similar to :func:`flesch_kincaid_grade_level()`
      and :func:`smog_index()`, but using characters per word instead of syllables.
  
      Higher value => more difficult text.
  
      Args:
          doc
  
      References:
          https://en.wikipedia.org/wiki/Coleman%E2%80%93Liau_index
      """
      words = tuple(utils.get_words(doc))
      n_sents = basics.n_sents(doc)
      n_words = basics.n_words(words)
      n_chars = basics.n_chars(words)
      return (
          (5.879851 * n_chars / n_words)
          - (29.587280 * n_sents / n_words)
          - 15.800804
      )
  
file_path: textacy/src/textacy/text_stats/readability.py
imports: import logging
  import math
  import statistics
  from typing import Optional
  from spacy.tokens import Doc
  from ..None import errors
  from .None import basics, utils
label_desc: Use image node_id 3 for calling a global function with example usage: coleman_liau_index(doc) and returns: unknown