def g(x):
    for i in range(x):
        print(i)

def f(n):
    i = n
    while i > 0:
        g(n)
        i -= 1

6: c_1
7, 9:  c_2
8:  The cost of line 8 is not a constant, since the function calls g(n), the runtime of which depends on n.  So look at g(x).  g(x) take time c_3 x.  So the cost of line 8 is c_3 n.

Line 6:  1 time
Lines 7, 9:  n times
Line 8:  n times

Total cost:

c_1 + c_2 n + c_3 n * n

Theta(n^2)