Repository: yt-dlp/yt-dlp
File: yt_dlp/utils.py (Python)

Code before:
                result = obj.groups()
            elif traverse_string:
                branching = False
                result = str(obj)
            else:
                result = ()

        elif callable(key):
            branching = True
            if isinstance(obj, collections.abc.Mapping):
                iter_obj = obj.items()
            elif is_sequence(obj):
                iter_obj = enumerate(obj)
            elif isinstance(obj, re.Match):
                iter_obj = itertools.chain(
                    enumerate((obj.group(), *obj.groups())),
                    obj.groupdict().items())
            elif traverse_string:
                branching = False
                iter_obj = enumerate(str(obj))
            else:
                iter_obj = ()

            result = (v for k, v in iter_obj if try_call(key, args=(k, v)))
            if not branching:  # string traversal
                result = "".join(result)

        elif isinstance(key, dict):
            iter_obj = ((k, _traverse_obj(obj, v, False, is_last)) for k, v in key.items())
            result = {
                k: v if v is not None else default for k, v in iter_obj
                if v is not None or default is not NO_DEFAULT
            } or None

        elif isinstance(obj, collections.abc.Mapping):
            result = (obj.get(key) if casesense or (key in obj) else
                      next((v for k, v in obj.items() if casefold(k) == key), None))

        elif isinstance(obj, re.Match):
            if isinstance(key, int) or casesense:
                with contextlib.suppress(IndexError):
                    result = obj.group(key)

            if isinstance(key, str):
                result = next((v for k, v in obj.groupdict().items() if casefold(k) == key), None)

        elif isinstance(key, (int, slice)):
            if not is_sequence(obj):
                if traverse_string:
                    with contextlib.suppress(IndexError):
                        result = str(obj)[key]

Review comment (suggestion):
```suggestion
                result = ''.join(result)
```

Code after:
                result = obj.groups()
            elif traverse_string:
                branching = False
                result = str(obj)
            else:
                result = ()

        elif callable(key):
            branching = True
            if isinstance(obj, collections.abc.Mapping):
                iter_obj = obj.items()
            elif is_sequence(obj):
                iter_obj = enumerate(obj)
            elif isinstance(obj, re.Match):
                iter_obj = itertools.chain(
                    enumerate((obj.group(), *obj.groups())),
                    obj.groupdict().items())
            elif traverse_string:
                branching = False
                iter_obj = enumerate(str(obj))
            else:
                iter_obj = ()

            result = (v for k, v in iter_obj if try_call(key, args=(k, v)))
            if not branching:  # string traversal
                result = ''.join(result)

        elif isinstance(key, dict):
            iter_obj = ((k, _traverse_obj(obj, v, False, is_last)) for k, v in key.items())
            result = {
                k: v if v is not None else default for k, v in iter_obj
                if v is not None or default is not NO_DEFAULT
            } or None

        elif isinstance(obj, collections.abc.Mapping):
            result = (obj.get(key) if casesense or (key in obj) else
                      next((v for k, v in obj.items() if casefold(k) == key), None))

        elif isinstance(obj, re.Match):
            if isinstance(key, int) or casesense:
                with contextlib.suppress(IndexError):
                    result = obj.group(key)

            elif isinstance(key, str):
                result = next((v for k, v in obj.groupdict().items() if casefold(k) == key), None)

        elif isinstance(key, (int, slice)):
            if not is_sequence(obj):
                if traverse_string:
                    with contextlib.suppress(IndexError):
                        result = str(obj)[key]