class_docstr: Test the PCA visualizer
class_docstr_tok: ["Test","the","PCA","visualizer"]
docstr: Test that fit returns self.
docstr_tok: ["Test","that","fit","returns","self","."]
code: def test_fit(self):
      """
      Test that fit returns self.
      """
      pca = PCA()
      assert pca.fit(*self.discrete) is pca
  
imports: import sys
  import pytest
  import numpy
  import numpy.testing
  from unittest import mock
  from tests.base import VisualTestCase, IS_WINDOWS_OR_CONDA
  from yellowbrick.features.pca import *
  from yellowbrick.exceptions import YellowbrickError, NotFitted
label_desc: Use image node_id 4 for calling the TestPCA obj's underlying member method code with example usage: obj.test_fit() without return types