using double for loop in one line within a function

Question

I have a function that accepts two arguments. for instance:

def sum(a,b):
   s = a+b
   return s

and I plan to make a dataframe using following pseudocode:

for a in range(1,10):
  for b in range(100,200):
       add(a,b)

and then i want to create a dataframe like:

DF:
A     B     Sum
1     100   101
1     101   102 
1     102   103
1     103   104
...

I knwo i can do it in one line if I ahve only one forloop like :

df = pd.DataFrame([sum(a,b) for a,b in zip(range(1,10),range(100.200))],
                  columns=['A', 'B', 'Sum'])

However this will not repeat A for every B. How can i add a for loop inside another in one line?