class_docstr: The scansion symbols used can be configured by passing a suitable constants class to
  the constructor.
docstr: For hendecasyllables the last three feet of the verse are predictable
  and do not regularly allow substitutions.
  
  :param scansion: scansion line thus far
  :return: corrected line of scansion
  
  >>> print(HendecasyllableScanner().correct_antepenult_chain(
  ... "-U -UU UU UU UX").strip())
  -U -UU -U -U -X
docstr_tok: ["For","hendecasyllables","the","last","three","feet","of","the","verse","are","predictable","and","do","not","regularly","allow","substitutions",".",":","param","scansion",":","scansion","line","thus","far",":","return",":","corrected","line","of","scansion",">",">",">","print","(","HendecasyllableScanner","(",")",".correct_antepenult_chain","(","...","``","-U","-UU","UU","UU","UX","''",")",".strip","(",")",")","-U","-UU","-U","-U","-X"]
code: def correct_antepenult_chain(self, scansion: str) -> str:
      """
      For hendecasyllables the last three feet of the verse are predictable
      and do not regularly allow substitutions.
  
      :param scansion: scansion line thus far
      :return: corrected line of scansion
  
      >>> print(HendecasyllableScanner().correct_antepenult_chain(
      ... "-U -UU UU UU UX").strip())
      -U -UU -U -U -X
      """
      mark_list = string_utils.mark_list(scansion)
      vals = list(scansion.replace(" ", ""))
      new_vals = (
          vals[: len(vals) - 6]
          + [
              self.constants.TROCHEE
              + self.constants.TROCHEE
              + self.constants.STRESSED
          ]
          + vals[-1:]
      )
      corrected = "".join(new_vals)
      new_line = list(" " * len(scansion))
      for idx, car in enumerate(corrected):
          new_line[mark_list[idx]] = car
      return "".join(new_line)
  
file_path: cltk/src/cltk/prosody/lat/hendecasyllable_scanner.py
imports: import re
  import cltk.prosody.lat.string_utils
  from cltk.prosody.lat.metrical_validator import MetricalValidator
  from cltk.prosody.lat.scansion_constants import ScansionConstants
  from cltk.prosody.lat.scansion_formatter import ScansionFormatter
  from cltk.prosody.lat.syllabifier import Syllabifier
  from cltk.prosody.lat.verse import Verse
  from cltk.prosody.lat.verse_scanner import VerseScanner
label_desc: Use image node_id 4 for calling the HendecasyllableScanner obj's underlying member method code with example usage: obj.correct_antepenult_chain(scansion) and returns: str