This function returns the subsystems which have previously been initialized.

    Returns:
        Set[InitFlag]: Flags indicating which subsystems have been initialized.

def was_init():
    """This function returns the subsystems which have previously been initialized.

    Returns:
        Set[InitFlag]: Flags indicating which subsystems have been initialized.
    """
    mask = lib.SDL_WasInit(0)
    return enumtools.get_items(InitFlags, mask, {InitFlags.everything})