How can I implement case when aggregating between python and columns

I've used SQL and SAS before, and now I've recently moved to Python. I ran into a lot of problems. I'm still working on them, but a new question is driving me crazy:

import pandas
import numpy as np
data = {'Period':['2016-02','2016-02','2016-02','2016-02','2016-03','2016-03','2016-04'],
'Name':['a','b','c','c','d','e','v'],
'amount':[2,3,41,1,8,43,20],
'Credit':[5,2,45,50,9,21,32]}

How to get the same result with SQL:

select *,case when Period = '2016-02' then (amount/Credit)*1.2
              when Period = '2016-03' then (amount/Credit)*1.1
         else (amount/Credit)*1.0 end as Rate from data

or like in SAS:

data data;
set data;
if Period = '2016-02' then rate=(amount/Credit)*1.2;
else if Period = '2016-03' then rate=(amount/Credit)*1.1;
else rate=(amount/Credit)*1.0;
run;

even more:

select Period,min(amount,credit) from data group by Period;