code: def _orbitNumberBreaks(self):
          
  
          if self.orbit_index is None:
              raise ValueError('Orbit properties must be defined at ' +
                               'pysat.Instrument object instantiation.' +
                               'See Instrument docs.')
          else:
              try:
                  self.sat[self.orbit_index]
              except ValueError:
                  raise ValueError('Provided orbit index does not appear to ' +
                                   'exist in loaded data')
  
          # determine where the orbit index changes from one value to the next
          uniq_vals = self.sat[self.orbit_index].unique()
          orbit_index = []
          for val in uniq_vals:
              idx, = np.where(val == self.sat[self.orbit_index].values)
              orbit_index.append(idx[0])
  
          # create orbitbreak index, ensure first element is always 0
          if orbit_index[0] != 0:
              ind = np.hstack((np.array([0]), orbit_index))
          else:
              ind = orbit_index
          # number of orbits
          num_orbits = len(ind)
          # set index of orbit breaks
          self._orbit_breaks = ind
          # set number of orbits for the day
          self.num = num_orbits
docs: Determine where orbital breaks in a dataset with orbit numbers occur.
  
          Looks for changes in unique values.