Return list of files in `path` that have a suffix in `extensions`; optionally `recurse`.

def get_files(path:PathOrStr, extensions:Collection[str]=None, recurse:bool=False,
              include:Optional[Collection[str]]=None)->FilePathList:
    "Return list of files in `path` that have a suffix in `extensions`; optionally `recurse`."
    if recurse:
        res = []
        for i,(p,d,f) in enumerate(os.walk(path)):
            # skip hidden dirs
            if include is not None and i==0:  d[:] = [o for o in d if o in include]
            else:                             d[:] = [o for o in d if not o.startswith('.')]
            res += _get_files(path, p, f, extensions)
        return res
    else:
        f = [o.name for o in os.scandir(path) if o.is_file()]
        return _get_files(path, path, f, extensions)