Find the running time equation of this Python function

def foo(L): # L is a list with n numbers

if L==[]:

return 5

s=0

for x in L:

s=s+x

A = L[0: len(L)//4] B = L[len(L)//4 : len(L)//2] C = L[len(L)//2 : 3*len(L)//4] return foo(A) + foo(B) + foo(C) + s