code: def test_colorbar_raises_value_error():
      """Test that a non matbplotlib axis object raises an value error."""
      with pytest.raises(AttributeError, match="requires a matplotlib"):
          ep.colorbar(list())
      plt.close()
  
imports: import pytest
  import matplotlib.pyplot
  import earthpy.plot
label_desc: Use image node_id 2 for calling a global function with example usage: test_colorbar_raises_value_error() without return types