[python functions]calculation sequence when "return" nested in for loop

Question

what's the differences between the following two functions:
[func1]
def func(x):
res = 0
for i in range(x):
res += i
return res

print(func(4))

[func2]
def func(x):
res = 0
for i in range(x):
res += i
return res

print(func(4))

func1 output is 0 and func2 outputs 6.BUT as referenced to the tutorial "Once you return a value from a function, it immediately stops being executed. Any code after the return statement will never happen." I assume both functions end up with :res=0, i=0, thus res+=i outputs 0.

Answer 1

in func1, return is nested in for loop. so fort value of i = 0, res=0 and return 0 => break for loop

in func2, return is after for loop.
so i=0=> res=0;i=1=>res=1;i=2=>res=3 and i=3=> res=6
i=4 => break for loop
next action is return res => output 6

Answer 2

Indentation is the difference. In the firs function it stops in the first iteration, because return comes there inside the for loop. Never ever use return inside the for loop!!!