Adds tick event function to TickProcess

pydyton/core.py

@@ -9,6 +9,7 @@ class Process:
 
     def process(self, *args):
         raise NotImplementedError
+        yield None
 
 
 class TickProcess(Process):
@@ -16,6 +17,9 @@ class TickProcess(Process):
         super().__init__()
         if tick < 1:
             raise ValueError('tick must be greatert than or equal to 1')
-        self.tick = tick
+        self.__tick = tick
+
+    def tick(self):
+        return self.env.timeout(self.__tick)