Help with "For loop"

[Vaelyn]

Hello. I'm a programming beginner and I am having trouble with something that would be considered really basic.

The following example code won't run:

import csv
global de, ep
DN = 0.200
SCH = 40
with open("Di_Tub.csv", "r") as f3:
    reader2 = csv.reader(f3, delimiter=';')
    for row3 in reader2:
        if row3[0] == DN:
            if row3[1] == SCH:
                de = float(row3[2])
                ep = float(row3[3])
print(de, ep)

I am getting this error:

print(de)
NameError: name 'de' is not defined

Can anyone help me?