class_docstr: Suggested backoff chain; includes at least on of each
  type of major sequential backoff class from backoff.py.
docstr: Lemmatize a list of words.
  
  >>> lemmatizer = GreekBackoffLemmatizer()
  >>> from cltk.alphabet.text_normalization import cltk_normalize
  >>> word = cltk_normalize('διοτρεφές')
  >>> lemmatizer.lemmatize([word])
  [('διοτρεφές', 'διοτρεφής')]
  >>> republic = cltk_normalize("κατέβην χθὲς εἰς Πειραιᾶ μετὰ Γλαύκωνος τοῦ Ἀρίστωνος")
  >>> lemmatizer.lemmatize(republic.split())
  [('κατέβην', 'καταβαίνω'), ('χθὲς', 'χθές'), ('εἰς', 'εἰς'), ('Πειραιᾶ', 'Πειραιεύς'), ('μετὰ', 'μετά'), ('Γλαύκωνος', 'Γλαύκων'), ('τοῦ', 'ὁ'), ('Ἀρίστωνος', 'Ἀρίστων')]
code: def lemmatize(self, tokens: List[str]):
      """
      Lemmatize a list of words.
  
      >>> lemmatizer = GreekBackoffLemmatizer()
      >>> from cltk.alphabet.text_normalization import cltk_normalize
      >>> word = cltk_normalize('διοτρεφές')
      >>> lemmatizer.lemmatize([word])
      [('διοτρεφές', 'διοτρεφής')]
      >>> republic = cltk_normalize("κατέβην χθὲς εἰς Πειραιᾶ μετὰ Γλαύκωνος τοῦ Ἀρίστωνος")
      >>> lemmatizer.lemmatize(republic.split())
      [('κατέβην', 'καταβαίνω'), ('χθὲς', 'χθές'), ('εἰς', 'εἰς'), ('Πειραιᾶ', 'Πειραιεύς'), ('μετὰ', 'μετά'), ('Γλαύκωνος', 'Γλαύκων'), ('τοῦ', 'ὁ'), ('Ἀρίστωνος', 'Ἀρίστων')]
      """
  
      lemmas = self.lemmatizer.lemmatize(tokens)
      return lemmas
  
file_path: cltk/src/cltk/lemmatize/grc.py
imports: import os
  from typing import List
  from cltk.lemmatize.backoff import DictLemmatizer, IdentityLemmatizer, RegexpLemmatizer, UnigramLemmatizer
  from cltk.utils import CLTK_DATA_DIR
  from cltk.utils.file_operations import open_pickle
label_desc: Use image node_id 3 for calling the GreekBackoffLemmatizer obj's underlying member method code with example usage: obj.lemmatize(tokens) and returns: lemmas