new rate_func manim 2019

[GustavoSantosBahia]

Hi! How can I create a new rate_func, in manim 2019.
example:
def aceleration_scene(t):
Rx = 3
Ry = 2
Rx0 = 0
Ry0 = 0
w1 = 1.3
w2 = 1.7
ax = Rxnp.cos(w1t) + Rx0 - Rx*(w12)np.cos(w1t)
ay = Rynp.sin(w2t) + Ry0 - Ry*(w22)np.sin(w2t)
return ax+ay