code: def addTerminalState(self, state):
          
          table = self._copy()
          table.table[state] = {}
          return table
docs: Create a new L{TransitionTable} with all of the same transitions as
          this L{TransitionTable} plus a new state with no transitions.
  
          @param state: The new state to include in the new table.
  
          @return: The newly created L{TransitionTable}.