message: removed redundent code
diff: @@ -2838,13 +2838,7 @@ def _ssim_helper(x, y, reducer, max_val, compensation=1.0, k1=_SSIM_K1, k2=_SSIM
  A pair containing the luminance measure, and the contrast-structure measure.
  """
  - if k1 is None:
  - c1 = (_SSIM_K1 * max_val) ** 2
  - else:
  c1 = (k1 * max_val) ** 2
  - if k2 is None:
  - c2 = (_SSIM_K2 * max_val) ** 2
  - else:
  c2 = (k2 * max_val) ** 2
  # SSIM luminance measure is
  