What is the mathematical formulation of the probit function in SAS?

Question

Can you please share the math for probit function available in sas. I am trying to replicate it in Python. SAS:

data one;
x=probit(0.008);
put x=;                                          
run;

Output:

x
-2.408915546

I tried below in python: Values do not match

def normpdf(x, mean, sd):
   var = float(sd)**2
   denom = (2*math.pi*var)**.5
   num = math.exp(-(float(x)-float(mean))**2/(2*var))
   return num/denom
normpdf(0.008,0,1) 
0.3989295144527161

Please share the correct math for probit function