code: def sort_func(self, key):
          
          if key == self._KEYS.SCHEMA:
              return 'aaa'
          if key == self._KEYS.NAME:
              return 'aab'
          if key == self._KEYS.SOURCES:
              return 'aac'
          if key == self._KEYS.ALIAS:
              return 'aad'
          if key == self._KEYS.MODELS:
              return 'aae'
          if key == self._KEYS.PHOTOMETRY:
              return 'zzy'
          if key == self._KEYS.SPECTRA:
              return 'zzz'
          return key
docs: Used to sort keys when writing Entry to JSON format.
  
          Should be supplemented/overridden by inheriting classes.