add main and optional sections

ch02/01_main-chapter-code/README.md

@@ -1,5 +1,9 @@
 # Chapter 2: Working with Text Data
 
+### Main Chapter Code
+
 - [ch02.ipynb](ch02.ipynb) contains all the code as it appears in the chapter
-- [dataloader.ipynb](dataloader.ipynb) is a minimal notebook with the main data loading pipeline implemented in this chapter
 
+### Optional Code
+
+- [dataloader.ipynb](dataloader.ipynb) is a minimal notebook with the main data loading pipeline implemented in this chapter

ch03/01_main-chapter-code/README.md

@@ -1,5 +1,10 @@
 # Chapter 3: Coding Attention Mechanisms
 
+### Main Chapter Code
+
 - [ch03.ipynb](ch03.ipynb) contains all the code as it appears in the chapter
+
+### Optional Code
+
 - [multihead-attention.ipynb](multihead-attention.ipynb) is a minimal notebook with the main data loading pipeline implemented in this chapter
 

ch04/01_main-chapter-code/README.md

@@ -1,6 +1,11 @@
 # Chapter 4: Implementing a GPT Model from Scratch To Generate Text
 
+### Main Chapter Code
+
 - [ch04.ipynb](ch04.ipynb) contains all the code as it appears in the chapter
 - [previous_chapters.py](previous_chapters.py) is a Python module that contains the `MultiHeadAttention` module from the previous chapter, which we import in [ch04.ipynb](ch04.ipynb) to create the GPT model
+
+### Optional Code
+
 - [gpt.py](gpt.py) is a standalone Python script file with the code that we implemented thus far, including the GPT model we coded in this chapter
 

ch04/README.md

@@ -4,6 +4,7 @@
 
 - [01_main-chapter-code](01_main-chapter-code) contains the main chapter code.
 
-## Bonus Materials
+## ### Optional Code
+
+- [02_performance-analysis](02_performance-analysis) contains optional code analyzing the performance of the GPT model(s) implemented in the main chapter.
 
-- [02_performance-analysis](02_performance-analysis) contains optional code analyzing the performance of the GPT model(s) implemented in the main chapter.

ch05/01_main-chapter-code/README.md

@@ -1,9 +1,14 @@
 # Chapter 5: Pretraining on Unlabeled Data
 
+### Main Chapter Code
+
 - [ch05.ipynb](ch05.ipynb) contains all the code as it appears in the chapter
 - [previous_chapters.py](previous_chapters.py) is a Python module that contains the `MultiHeadAttention` module and `GPTModel` class from the previous chapters, which we import in [ch05.ipynb](ch05.ipynb) to pretrain the GPT model
-- [gpt_train.py](gpt_train.py) is a standalone Python script file with the code that we implemented in [ch05.ipynb](ch05.ipynb) to train the GPT model (you can think of it as a code file summarizing this chapter)
-- [gpt_generate.py](gpt_generate.py) is a standalone Python script file with the code that we implemented in [ch05.ipynb](ch05.ipynb) to load and use the pretrained model weights from OpenAI
 - [gpt_download.py](gpt_download.py) contains the utility functions for downloading the pretrained GPT model weights
 - [exercise-solutions.ipynb](exercise-solutions.ipynb) contains the exercise solutions for this chapter
 
+### Optional Code
+
+- [gpt_train.py](gpt_train.py) is a standalone Python script file with the code that we implemented in [ch05.ipynb](ch05.ipynb) to train the GPT model (you can think of it as a code file summarizing this chapter)
+- [gpt_generate.py](gpt_generate.py) is a standalone Python script file with the code that we implemented in [ch05.ipynb](ch05.ipynb) to load and use the pretrained model weights from OpenAI
+

ch06/01_main-chapter-code/README.md

@@ -1,8 +1,13 @@
 # Chapter 6: Finetuning for Classification
 
+### Main Chapter Code
+
 - [ch06.ipynb](ch06.ipynb) contains all the code as it appears in the chapter
-- [previous_chapters.py](previous_chapters.py) is a Python module that contains the GPT model we coded and trained in previous chapters, alongside many utility functions, which we reuse in this chapter
-- [gpt-class-finetune.py](gpt-class-finetune.py) is a standalone Python script file with the code that we implemented in [ch06.ipynb](ch06.ipynb) to finetune the GPT model (you can think of it as a chapter summary)
+- [previous_chapters.py](previous_chapters.py)  is a Python module that contains the GPT model we coded and trained in previous chapters, alongside many utility functions, which we reuse in this chapter
 - [gpt_download.py](gpt_download.py) contains the utility functions for downloading the pretrained GPT model weights
 - [exercise-solutions.ipynb](exercise-solutions.ipynb) contains the exercise solutions for this chapter
 
+### Optional Code
+
+- [gpt-class-finetune.py](gpt-class-finetune.py) is a standalone Python script file with the code that we implemented in [ch06.ipynb](ch06.ipynb) to finetune the GPT model (you can think of it as a chapter summary)
+

ch07/01_main-chapter-code/README.md

@@ -1,3 +1,11 @@
 # Chapter 7: Finetuning to Follow Instructions
 
+### Main Chapter Code
+
+- [ch07.ipynb](ch07.ipynb) contains all the code as it appears in the chapter
+- [previous_chapters.py](previous_chapters.py)  is a Python module that contains the GPT model we coded and trained in previous chapters, alongside many utility functions, which we reuse in this chapter
+- [gpt_download.py](gpt_download.py) contains the utility functions for downloading the pretrained GPT model weights
+
+### Optional Code
+
 In progress ...