Auto generate __all__ variable

gen_all.py

#!/usr/bin/env python3
import sys

# NOTE: redbaron have no full support of python3.7, so construction such as `foo = {**bar}` may cause crash
from redbaron import RedBaron

def generate_all_variable(file_name: str):
    with open(file_name, 'r+') as src:
        rb = RedBaron(src.read())

        _all_ = None 
        public_items = []
        last_import_idx = None

        for idx, node in enumerate(rb):
          
            # If __all__ already exists, we will rewrite it
            if node.type == 'assignment' and str(node.name) == '__all__':
                _all_ = node
                
            # Memorizing the last import position to insert __all__, if it's not exists yet
            elif node.type in ('import', 'from_import'):
                last_import_idx = idx + 1
            
            # Collect all public classes/functions names
            elif node.type in ('class', 'def') and not node.name.startswith('_'):
                public_items.append(node.name)

        if public_items:
            new_all_ = f'__all__ = {tuple(sorted(public_items))}'
            
            if _all_ is not None:
                all_idx = rb.index(_all_)
                rb.remove(_all_)
                rb.insert(all_idx, new_all_)
            else:
                rb.insert(last_import_idx or 0, new_all_)
                rb.insert(last_import_idx or 0, '\n')

        src.seek(0)
        src.truncate()
        src.write(rb.dumps())


if __name__ == '__main__':
    # The first argument is required and must be an absolute path to *.py file
    generate_all_variable(sys.argv[1])