sum of nested list in Python

Question

I try to sum a list of nested elements

e.g, numbers=[1,3,5,6,[7,8]] should produce sum=30

I wrote the following code :

Answer 1

 def sum_nest_lst(lst):
         t=0
         for l in lst:
             if(type(l)==int):
                 t=t+l
             if(type(l)==list):
                 t=t+sum(l)
         print(t)