code: def test_aes_overwrite():
      with pytest.warns(PlotnineWarning):
          geom_vline(aes(color="x"), xintercept=2)
  
imports: import pandas
  import pytest
  from plotnine import aes, geom_point, geom_vline, ggplot
  from plotnine.exceptions import PlotnineError, PlotnineWarning
label_desc: Use image node_id 3 for calling a global function with example usage: test_aes_overwrite() without return types