from pathlib import Path
from typing import Iterator

def find_files(folder: str, extension: str) -> Iterator[Path]:
    if not Path(folder).exists():
        raise FileExistsError("Folder isn't exist")
    return Path(folder).rglob(f"*{extension}")

files: Iterator[Path] = find_files("./test", ".py")
for f in files:
    print(f.name, f.stat().st_size, "bytes")