To find the comment related nodes, I will look at the higher level nodes. Hence, I can see that the 'comment' nodes with ids = [1, 2], represent comments in the code. Incorporating each of these nodes, I can make a general rule to extract the comments.

This python script can be executed:

```py
if code_snippet.startswith('{-'):
    # As the snippets start with '{-' and end with '-}', we can remove two characters from both ends to get the required snippet
    extracted = code_snippet[2:-2].strip()
elif code_snippet.startswith('--'):
    # As the snippets start with '--', we can remove two characters from the start to get the required snippet
    extracted = code_snippet[2:].strip()
```

This script will extract the comments from the given code snippets, which are "Here is a comment above a module." and "hi".