def METHOD_NAME(mask, radius, num_classes):
    """
    Convert a segmentic segmentation mask (H, W) to a binary edge mask(H, W).
    Args:
        mask (np.ndarray): Label mask with shape (H, W)
        radius (int|float): Radius of edge.
        num_classes (int): Number of classes.
    Returns:
        np.ndarray: Edge mask with shape(H, W).
    """
    mask = mask.squeeze()
    onehot = mask_to_onehot(mask, num_classes)
    edge = onehot_to_binary_edge(onehot, radius)
    return edge