To find the function definition related nodes, I will look at the higher level nodes. Hence, I can see that the 'function_identifier' nodes with ids = [21], represent definition of functions in the code. Incorporating each of these nodes, I can make a general rule to extract the definitions.

This python script can be executed:

```py
# we directly get the function name from the snippet
extracted = code_snippet.strip()
```

This script works because the 'function_identifier' node has a code snippet that directly contains the function name, without any additional keywords or brackets. Therefore, we can simply strip any leading or trailing whitespace to get the function name.