code: def brightness_prob(self, clip=True):
          
          thresh = 0.11
          bp = np.minimum(thresh, self.nir) / thresh
          if clip:
              bp[bp > 1] = 1
              bp[bp < 0] = 0
          return bp
docs: The brightest water may have Band 5 reflectance
          as high as LE07_clip_L1TP_039027_20150529_20160902_01_T1_B1.TIF.11
          Equation 10 (Zhu and Woodcock, 2012)
          Parameters
          ----------
          nir: ndarray
          clip: boolean
          Output
          ------
          ndarray:
              brightness probability, constrained LE07_clip_L1TP_039027_20150529_20160902_01_T1_B1.TIF..1