code: def basic_chart():
      data = pd.DataFrame(
          {
              "a": ["A", "B", "C", "D", "E", "F", "G", "H", "I"],
              "b": [28, 55, 43, 91, 81, 53, 19, 87, 52],
          }
      )
  
      return alt.Chart(data).mark_bar().encode(x="a", y="b")
  
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 3 for calling a global function with example usage: basic_chart() and returns: alt