code: def test_read_arpa():
      from speechbrain.lm.arpa import read_arpa
      import io
  
      with io.StringIO() as f:
          print("Anything can be here", file=f)
          print("", file=f)
          print("\\data\\", file=f)
          print("ngram 1=2", file=f)
          print("ngram 2=3", file=f)
          print("", file=f)  # Ends data section
          print("\\1-grams:", file=f)
          print("-0.6931 a", file=f)
          print("-0.6931 b 0.", file=f)
          print("", file=f)  # Ends unigram section
          print("\\2-grams:", file=f)
          print("-0.6931 a a", file=f)
          print("-0.6931 a b", file=f)
          print("-0.6931 b a", file=f)
          print("", file=f)  # Ends bigram section
          print("\\end\\", file=f)  # Ends whole file
          f.seek(0)
          num_grams, ngrams, backoffs = read_arpa(f)
      assert num_grams[1] == 2
      assert num_grams[2] == 3
      assert ngrams[1][()]["a"] == -0.6931
      assert ngrams[1][()]["b"] == -0.6931
      assert ngrams[2][("a",)]["a"] == -0.6931
      assert ngrams[2][("a",)]["b"] == -0.6931
      assert ngrams[2][("b",)]["a"] == -0.6931
      assert backoffs[1][("b",)] == 0.0
      assert list(backoffs[1].keys()) == [("b",)]
  
      # Badly formatted ARPA file:
      with io.StringIO() as f:
          print("Anything can be here", file=f)
          print("", file=f)
          print("\\data\\", file=f)
          print("ngram 1=1", file=f)
          print("", file=f)  # Ends data section
          print("\\1-grams:", file=f)
          print("-0.6931 a", file=f)
          print("", file=f)  # Ends bigram section
          # BUT! \end\ is missing
          f.seek(0)
  
          with pytest.raises(ValueError):
              num_grams, ngrams, backoffs = read_arpa(f)
  
      # You can theoretically have many ARPA LMs in one file:
      with io.StringIO() as f:
          for _ in range(3):
              print("Anything can be here", file=f)
              print("", file=f)
              print("\\data\\", file=f)
              print("ngram 1=2", file=f)
              print("ngram 2=3", file=f)
              print("", file=f)  # Ends data section
              print("\\1-grams:", file=f)
              print("-0.6931 a", file=f)
              print("-0.6931 b 0.", file=f)
              print("", file=f)  # Ends unigram section
              print("\\2-grams:", file=f)
              print("-0.6931 a a", file=f)
              print("-0.6931 a b", file=f)
              print("-0.6931 b a", file=f)
              print("", file=f)  # Ends bigram section
              print("\\end\\", file=f)  # Ends whole file
          f.seek(0)
          # Now read three times:
          num_grams, ngrams, backoffs = read_arpa(f)
          num_grams, ngrams, backoffs = read_arpa(f)
          num_grams, ngrams, backoffs = read_arpa(f)
  
          # And it still worked:
          assert num_grams[1] == 2
          assert num_grams[2] == 3
          assert ngrams[1][()]["a"] == -0.6931
          assert ngrams[1][()]["b"] == -0.6931
          assert ngrams[2][("a",)]["a"] == -0.6931
          assert ngrams[2][("a",)]["b"] == -0.6931
          assert ngrams[2][("b",)]["a"] == -0.6931
          assert backoffs[1][("b",)] == 0.0
          assert list(backoffs[1].keys()) == [("b",)]
  
          # Try to read a fourth time, though, and it will fail
          with pytest.raises(ValueError):
              num_grams, ngrams, backoffs = read_arpa(f)
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_read_arpa() without return types