code: def setUp(self):
      self.documents = [
          ["cat", "dog", "mouse"],
          ["cat", "lion"],
          ["cat", "lion"],
      ]
      self.dictionary = Dictionary(self.documents)
  
      self.expected_avgdl = sum(map(len, self.documents)) / len(
          self.documents
      )
  
imports: from collections import defaultdict
  import math
  import unittest
  from gensim.models.bm25model import BM25ABC
  from gensim.models import OkapiBM25Model, LuceneBM25Model, AtireBM25Model
  from gensim.corpora import Dictionary
label_desc: Use image node_id 1 for calling the BM25ABCTest obj's underlying member method code with example usage: obj.setUp() without return types