code: def test_get_backward_relationships(es):
      relationships = es.get_backward_relationships("sessions")
      assert len(relationships) == 1
      assert relationships[0]._parent_dataframe_name == "sessions"
      assert relationships[0]._child_dataframe_name == "log"
  
      relationships = es.get_backward_relationships("customers")
      assert len(relationships) == 1
      assert relationships[0]._parent_dataframe_name == "customers"
      assert relationships[0]._child_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 8 for calling a global function with example usage: test_get_backward_relationships(es) without return types