code: def test_basic(self):
      img = np.ones((50, 50, 3), dtype=np.uint8)
      bands = histograms(img, 255)
      for band in bands:
          np.testing.assert_equal(band.sum(), 50**2)
  
imports: import numpy
  from skimage.io._plugins._histograms import histograms
label_desc: Use image node_id 1 for calling the TestHistogram obj's underlying member method code with example usage: obj.test_basic() without return types