code: def test_graticule():
      data = alt.graticule()
      assert data.to_dict() == {"graticule": True}
  
      data = alt.graticule(step=[15, 15])
      assert data.to_dict() == {"graticule": {"step": [15, 15]}}
  
imports: import io
  import json
  import operator
  import os
  import pathlib
  import tempfile
  import jsonschema
  import pytest
  import pandas
  import altair.vegalite.v5
label_desc: Use image node_id 41 for calling a global function with example usage: test_graticule() without return types