def METHOD_NAME(center_x, center_y, r, x_grid, y_grid):
    """
    :param center_x: x-coordinate of center position of circular mask
    :param center_y: y-coordinate of center position of circular mask
    :param r: radius of mask in pixel values
    :param x_grid: x-coordinate grid
    :param y_grid: y-coordinate grid
    :return: mask array of shape x_grid with =0 inside the radius and =1 outside
    :rtype: array of size of input grid with integers 0 or 1
    """
    x_shift = x_grid - center_x
    y_shift = y_grid - center_y
    R = np.sqrt(x_shift * x_shift + y_shift * y_shift)
    mask = np.empty_like(R, dtype="int")
    mask[R > r] = 1
    mask[R <= r] = 0
    return mask