Collapsible class diagram

Author: dancergraham

chapter01_strategy/readme.md

@@ -2,6 +2,8 @@
 
 > **Strategy**: defines a family of algorithms, encapsulates each one and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it.
 
+<details><summary>Class Diagram</summary><p>
+
 ```mermaid
 classDiagram
 Client "1" --> "1" Strategy
@@ -23,4 +25,7 @@ Strategy "1" <|.. "*" ConcreteStrategyB
     }
 ```
 
+</p></details>
+
+
 I think the more pythonic approach would be to define methods rather than classes, and this would not violate the above definition.  The class-based approach is needed in Java and has the advantage of explicitly setting out the required method in an abstract base class.