code: def sample_chart():
      df = pd.DataFrame({"A": [1, 2], "B": [10, 20]})
      return alt.Chart(df).mark_point().encode(x="A", y="B")
  
file_path: deepvariant/deepvariant/dashboard_utils_test.py
imports: import io
  from absl.testing import absltest
  from absl.testing import parameterized
  import altair
  import pandas
  from deepvariant import dashboard_utils
label_desc: Use image node_id 1 for calling a global function with example usage: sample_chart() and returns: alt