code: def test_unpivot_bad_cols():
      frame = pd.DataFrame({"x": range(10), "y": range(10)})
  
      with pytest.raises(KeyError):
          unpivot_frame(frame, x="foo")
  
      with pytest.raises(KeyError):
          unpivot_frame(frame, y="foo")
  
      with pytest.raises(KeyError):
          unpivot_frame(frame, x=("x", "foo"))
  
      with pytest.raises(KeyError):
          unpivot_frame(frame, y=("y", "foo"))
  
imports: import pytest
  import pandas
  import numpy
  from pdvega._utils import infer_vegalite_type, unpivot_frame, validate_aggregation
label_desc: Use image node_id 3 for calling a global function with example usage: test_unpivot_bad_cols() without return types