Stimuli method. This method is a Python function generator that is automatically called by the Testbench method to generate all the stimuli. As a Python function generator, the yield instruction have to be used at the end of each stimuli computation.
affect permits to affect a value to a given signal as follow
self._stim.affect(self.Ck,0)
add permits to finish a step of simulation by add all the values to the current stimuli
self._stim.add()