code: def addLens(self, lens, date=None, info='', light_spectrum='visible'):
          '''
          lens -> instance of LensDistortion or saved file
          '''
          self._registerLight(light_spectrum)
          date = _toDate(date)
  
          if not isinstance(lens, LensDistortion):
              l = LensDistortion()
              l.readFromFile(lens)
              lens = l
  
          f = self.coeffs['lens']
          if light_spectrum not in f:
              f[light_spectrum] = []
          f[light_spectrum].insert(_insertDateIndex(date, f[light_spectrum]),
                                   [date, info, lens.coeffs]f addLens(self, lens, date=None, info='', light_spectrum='visible'):
          '''
          lens -> instance of LensDistortion or saved file
          '''
          self._registerLight(light_spectrum)
          date = _toDate(date)
  
          if not isinstance(lens, LensDistortion):
              l = LensDistortion()
              l.readFromFile(lens)
              lens = l
  
          f = self.coeffs['lens']
          if light_spectrum not in f:
              f[light_spectrum] = []
          f[light_spectrum].insert(_insertDateIndex(date, f[light_spectrum]),
                                   [date, info, lens.coeffs])
docs: lens -> instance of LensDistortion or saved file