code: def test_dist_error(self):
      df = pdml.ModelFrame(
          np.random.randn(100, 5), columns=list("abcde")
      )
  
      msg = "a can't be ommitted when ModelFrame doesn't have target column"
      with pytest.raises(ValueError, match=msg):
          df.sns.distplot()
  
      df.target = df[["a", "b"]]
      self.assertTrue(df.has_multi_targets())
  
      msg = "a can't be ommitted when ModelFrame has multiple target columns"
      with pytest.raises(ValueError, match=msg):
          df.sns.distplot()
  
imports: import pytest
  import matplotlib
  import numpy
  import sklearn.datasets
  import pandas_ml
  import pandas_ml.util.testing
label_desc: Use image node_id 4 for calling the TestSeabornDistribution obj's underlying member method code with example usage: obj.test_dist_error() without return types