from typing import AnyStr
from typing import Tuple
from typing import Optional


def split_chunk(part: AnyStr, char: AnyStr) -> Tuple[AnyStr, Optional[AnyStr]]:
    """Split chunk into two parts, based on given delimiter character.

    It will return tuple of those two chunks. If no such delim exists,
    the first element of tuple will have the complete chunk whereas the other
    will be None.
    """
    found = part.find(char)
    if found > -1:
        return part[: found + len(char)], part[found + len(char) :]

    return part, None