Flatten a list with comprehensions and a generator.

list_flatten.py

from typing import Generator, Any

def list_flatten(l: list) -> Generator[Any,None,None]:
    for item in l:
        if isinstance(item, list):
            yield from list_flatten(item)
        else:
            yield item

if __name__ == '__main__':
    data = [["a"],["b",["c",["d"]]]]
    flat_list = [item for item in list_flatten(data) if item]
    print(flat_list)