Update course_structure.md

course_structure.md

@@ -1,6 +1,6 @@
 ```mermaid
 
-graph TD
+flowchart TD
 
     M1(Git, Pull Requests, and code reviews)
     M2(Python functions, classes, and modules)
@@ -10,18 +10,29 @@ graph TD
     M6(Documentation)
     M7(Distributing your package)
 
-    B1(The bigger picture)
-    B2(Separations of concern)
-    B3(Abstraction and encapsulation)
-    B4(Designing for high performance)
-    B5(Testing your software)
-    B6(Separations of concerns in practice)
-    B7(Extensibility and flexibility)
-    B8(The rules and exceptions of inheritance)
+    B1[1. The bigger picture]
+    B2[2. Separations of concern]
+    B3[3. Abstraction and encapsulation]
+    B4[4. Designing for high performance]
+    B5[5. Testing your software]
+    B6[6. Separations of concerns in practice]
+    B7[7. Extensibility and flexibility]
+    B8[8. The rules and exceptions of inheritance]
+    B9[9. Keeping things lightweight]
+    B10[10. Achieving loose coupling]
 
     M1 --> M2 --> M3 --> M4 --> M5 --> M6 --> M7
 
     B1 --> M2
     B2 --> M2
+    B3 --> M3
+    B8 --> M3
     B4 --> M4
-```
+    B5 --> M4
+    B6 --> M5
+    B7 --> M6
+
+    B9 --> M7
+    B10 --> M7   
+    
+```