Determining if point on boundary using shapely?

I'm new to Python, and I want to test if a certain point lies ON the (boundary) of a polygon - not inside, not outside, just if it's on the boundary. The points and polygon already defined

polygon = [(3, 2), (5, 1), (7, 2), (8, 6), (9, 7), (11, 6), (10, 4), (12, 2), (15, 2), (16, 5), (19, 7), (18, 11), (14, 12), (11, 9), (5, 9), (2, 6)] 
Point_X = 14
Point_Y = 12

this point should be a boundary. How can I do that?