take input
while incorrect input:
take input
#Eg. Taking the month input for the first quarter of the year.
months = ['january', 'february', 'march']
month = input('Select the month').lower()
while month not in months:
month = input('Oops! Incorrect input. Select month again').lower()
while True:
try:
# Note: Python 2.x users should use raw_input, the equivalent of 3.x's input
age = int(input("Please enter your age: "))
except ValueError:
print("Sorry, I didn't understand that.")
#better try again... Return to the start of the loop
continue
else:
#age was successfully parsed!
#we're ready to exit the loop.
break
if age >= 18:
print("You are able to vote in the United States!")
else:
print("You are not able to vote in the United States.")