Python, Why is my script not running?

I've made a script to calculate the probability of a point in a tennis match, depending on the current score. But for some reason when I want to run my script nothing happens. Explination is on the script. Any suggestions? ## calculate the probability of server winning a single game, ## given p(winning single point) and current point score def fact(x): if x in [0, 1]: return 1 r = 1 for a in range(1, (x+1)): r = r*a return r def ch(a, b): return fact(a)/(fact(b)*fact(a-b)) def gameOutcome(s, a, b): return ch((a+b), a)*(s**a)*((1-s)**b)*s def gameProb(s=[0.6], v=2, w=1): ## function calculates the probability of server winning ## a single game, given p(winning any given point) [s], ## and the current point score. ## v, w = current game score, where love = 0, 15 = 1, etc. ## - e.g. 30-15 is v=2, w=1 ## check if game is already over: if v >= 4 and (v-w) >= 2: return 1 elif w >= 4 and (w-v) >= 2: return 0 else: pass ## if deuce or ad score e.g. 5-4, reduce to e.g. 3-2 while True: if (v+w) > 6: v -= 1 w -= 1 else: break ## specific probabilities: if w == 0: w0 = gameOutcome(s, 3-v, 0) else: w0 = 0 if w <= 1: w15 = gameOutcome(s, 3-v, 1-w) else: w15 = 0 if w <= 2: w30 = gameOutcome(s, 3-v, 2-w) else: w30 = 0 if v == 4: wAd, lAd = s, 0 d = 1-s elif w == 4: wAd, lAd = 0, 1-s d = s else: wAd, lAd = 0, 0 a = 3 - v b = 3 - w d = ch((a+b), a)*(s**a)*((1-s)**b) if v <= 2: l30 = gameOutcome((1-s), 3-w, 2-v) else: l30 = 0 if v <= 1: l15 = gameOutcome((1-s), 3-w, 1-v) else: l15 = 0 if v == 0: l0 = gameOutcome((1-s), 3-w, 0) else: l0 = 0 ## given d = prob of getting to deuce, ## math to divide up further outcomes denom = s**2 + (1-s)**2 wd = (d*(s**2))/denom ld = (d*((1-s)**2))/denom win = w0 + w15 + w30 + wd + wAd lose = l0 + l15 + l30 + ld + lAd Return win