code: def test_variables_from_mix(self):
      p = lm._RegressionPlotter("x", self.df.y + 1, data=self.df)
  
      npt.assert_array_equal(p.x, self.df.x)
      npt.assert_array_equal(p.y, self.df.y + 1)
      pdt.assert_frame_equal(p.data, self.df)
  
imports: import warnings
  import numpy
  import matplotlib
  import matplotlib.pyplot
  import pandas
  import pytest
  import numpy.testing
  import pandas.testing
  from seaborn import regression
  from seaborn.palettes import color_palette
label_desc: Use image node_id 3 for calling the TestRegressionPlotter obj's underlying member method code with example usage: obj.test_variables_from_mix() without return types