- Moved AbstractExpert

- Changed __init__ in AbstractExpert to abstract method

- Added comments

Author: cdorsman

patterns/other/blackboard.py

@@ -9,13 +9,27 @@
 https://en.wikipedia.org/wiki/Blackboard_system
 """
 
-from __future__ import annotations
-
-import abc
+from abc import ABC, abstractmethod
 import random
 
+class AbstractExpert(ABC):
+    """Abstract class for experts in the blackboard system."""
+    @abstractmethod
+    def __init__(self, blackboard: object) -> None:
+        self.blackboard = blackboard
+
+    @property
+    @abstractmethod
+    def is_eager_to_contribute(self):
+        raise NotImplementedError("Must provide implementation in subclass.")
+
+    @abstractmethod
+    def contribute(self):
+        raise NotImplementedError("Must provide implementation in subclass.")
+
 
 class Blackboard:
+    """The blackboard system that holds the common state."""
     def __init__(self) -> None:
         self.experts = []
         self.common_state = {
@@ -30,6 +44,7 @@ def add_expert(self, expert: AbstractExpert) -> None:
 
 
 class Controller:
+    """The controller that manages the blackboard system."""
     def __init__(self, blackboard: Blackboard) -> None:
         self.blackboard = blackboard
 
@@ -45,21 +60,11 @@ def run_loop(self):
         return self.blackboard.common_state["contributions"]
 
 
-class AbstractExpert(metaclass=abc.ABCMeta):
-    def __init__(self, blackboard: Blackboard) -> None:
-        self.blackboard = blackboard
-
-    @property
-    @abc.abstractmethod
-    def is_eager_to_contribute(self):
-        raise NotImplementedError("Must provide implementation in subclass.")
-
-    @abc.abstractmethod
-    def contribute(self):
-        raise NotImplementedError("Must provide implementation in subclass.")
-
-
 class Student(AbstractExpert):
+    """Concrete class for a student expert."""
+    def __init__(self, blackboard) -> None:
+        super().__init__(blackboard)
+
     @property
     def is_eager_to_contribute(self) -> bool:
         return True
@@ -72,6 +77,10 @@ def contribute(self) -> None:
 
 
 class Scientist(AbstractExpert):
+    """Concrete class for a scientist expert."""
+    def __init__(self, blackboard) -> None:
+        super().__init__(blackboard)
+
     @property
     def is_eager_to_contribute(self) -> int:
         return random.randint(0, 1)
@@ -84,6 +93,9 @@ def contribute(self) -> None:
 
 
 class Professor(AbstractExpert):
+    def __init__(self, blackboard) -> None:
+        super().__init__(blackboard)
+
     @property
     def is_eager_to_contribute(self) -> bool:
         return True if self.blackboard.common_state["problems"] > 100 else False