class_docstr: The scansion symbols used can be configured by passing a suitable constants class to
  the constructor.
class_docstr_tok: ["The","scansion","symbols","used","can","be","configured","by","passing","a","suitable","constants","class","to","the","constructor","."]
docstr: For pentameter the last two feet of the verse are predictable dactyls,
  and do not regularly allow substitutions.
  
  :param scansion: scansion line thus far
  :return: corrected line of scansion
  
  >>> print(PentameterScanner().correct_penultimate_dactyl_chain(
  ... "U  U  U  U  U  U  U  U  U  U  U  U  U  U"))
  U  U  U  U  U  U  U  -  U  U  -  U  U  U
docstr_tok: ["For","pentameter","the","last","two","feet","of","the","verse","are","predictable","dactyls",",","and","do","not","regularly","allow","substitutions",".",":","param","scansion",":","scansion","line","thus","far",":","return",":","corrected","line","of","scansion",">",">",">","print","(","PentameterScanner","(",")",".correct_penultimate_dactyl_chain","(","...","``","U","U","U","U","U","U","U","U","U","U","U","U","U","U","''",")",")","U","U","U","U","U","U","U","-","U","U","-","U","U","U"]
code: def correct_penultimate_dactyl_chain(self, scansion: str) -> str:
      """
      For pentameter the last two feet of the verse are predictable dactyls,
      and do not regularly allow substitutions.
  
      :param scansion: scansion line thus far
      :return: corrected line of scansion
  
      >>> print(PentameterScanner().correct_penultimate_dactyl_chain(
      ... "U  U  U  U  U  U  U  U  U  U  U  U  U  U"))
      U  U  U  U  U  U  U  -  U  U  -  U  U  U
      """
      mark_list = string_utils.mark_list(scansion)
      vals = list(scansion.replace(" ", ""))
      n_vals = (
          vals[:-7]
          + [self.constants.DACTYL + self.constants.DACTYL]
          + [vals[-1]]
      )
      corrected = "".join(n_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/pentameter_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 5 for calling the PentameterScanner obj's underlying member method code with example usage: obj.correct_penultimate_dactyl_chain(scansion) and returns: str