code: def test_find_backward_paths(es):
      paths = list(es.find_backward_paths("customers", "log"))
      assert len(paths) == 1
  
      path = paths[0]
  
      assert len(path) == 2
      assert path[0]._child_dataframe_name == "sessions"
      assert path[0]._parent_dataframe_name == "customers"
      assert path[1]._child_dataframe_name == "log"
      assert path[1]._parent_dataframe_name == "sessions"
  
imports: import pandas
  import pytest
  from featuretools import EntitySet
  from featuretools.tests.testing_utils import backward_path, forward_path
label_desc: Use image node_id 17 for calling a global function with example usage: test_find_backward_paths(es) without return types