code: def append_sources_from(self, other):
          
          # Get aliases lists from this `CatDict` and other
          self_aliases = self[self._KEYS.SOURCE].split(',')
          other_aliases = other[self._KEYS.SOURCE].split(',')
  
          # Store alias to `self`
          self[self._KEYS.SOURCE] = uniq_cdl(self_aliases + other_aliases)
  
          return
docs: Merge the source alias lists of two CatDicts.