code: def test_fallback_string():
      algo = basic.Fallback([basic.Memorized(simple_df), Bias()])
      assert "Fallback" in str(algo)
  
file_path: lkpy/tests/test_fallback.py
imports: from lenskit.algorithms import basic
  from lenskit.algorithms.bias import Bias
  from lenskit import util
  import pandas
  import numpy
  import binpickle
  import lenskit.util.test
  from pytest import approx
label_desc: Use image node_id 4 for calling a global function with example usage: test_fallback_string() without return types