'Draw a Gouraud-shaded triangle.
Parameters
points : array_like, shape=(3, 2)
Array of (x, y) points for the triangle.
colors : array_like, shape=(3, 4)
RGBA colors for each point of the triangle.
transform : `matplotlib.transforms.Transform`
An affine transform to apply to the points.'

def draw_gouraud_triangle(self, gc, points, colors, transform):

    raise NotImplementedError
