range condtion

find("1437143647666.png").inside().find("1437151470770.png")
wait(2)
while True:

for i in range(0,19):
    pass

click("1437151481432.png")
if exists("1437151493592.png"):

   print("yes")
else:
    print("No")

wait(2)

Scenerio - i want to delete my trash mails one by one upto 20 records

please tell me how to implment range condition in it.

It will be very good,if you write script here

Thanks,
Ravi