code: def test_missing_file_extension(simple_feat):
      output_path = "test1"
      with pytest.raises(
          ValueError, match="Please use a file extension"
      ):
          graph_feature(simple_feat, to_file=output_path)
  
imports: import json
  import os
  import re
  import graphviz
  import pytest
  from featuretools.feature_base import AggregationFeature, DirectFeature, FeatureOutputSlice, GroupByTransformFeature, IdentityFeature, TransformFeature, graph_feature
  from featuretools.primitives import Count, CumMax, Mode, NMostCommon, Year
label_desc: Use image node_id 5 for calling a global function with example usage: test_missing_file_extension(simple_feat) without return types