def view(filepath):
    """Open filepath with its default viewing application (platform-specific).

    Args:
        filepath: Path to the file to open in viewer.
    Raises:
        RuntimeError: If the current platform is not supported.
    """
    try:
        view_func = getattr(view, PLATFORM)
    except AttributeError:
        raise RuntimeError('platform %r not supported' % PLATFORM)
    view_func(filepath)