code: def test_cubehelix_n_colors(self):
      for n in [3, 5, 8]:
          pal = palettes.cubehelix_palette(n)
          assert len(pal) == n
  
imports: import colorsys
  import numpy
  import matplotlib
  import pytest
  import numpy.testing
  from seaborn import palettes, utils, rcmod
  from seaborn.external import husl
  from seaborn._compat import get_colormap
  from seaborn.colors import xkcd_rgb, crayons
label_desc: Use image node_id 28 for calling the TestColorPalettes obj's underlying member method code with example usage: obj.test_cubehelix_n_colors() without return types