Can't get my exception handling code to work

Question

I'm getting an EOF error. I think it has something to do with my input(). Do I need to put a loop in somewhere to continuously use input? ..

Write a program that calculates an adult's fat-burning heart rate, which is 70% of the difference between 220 and the person's age respectively. Complete fat_burning_heart_rate() to calculate the fat burning heart rate.

The adult's age must be between the ages of 18 and 75 inclusive. If the age entered is not in this range, raise a ValueError exception in get_age() with the message "Invalid age." Handle the exception in main and print the ValueError message along with "Could not calculate heart rate info."

Ex: If the input is:

35

the output is:

Fat burning heart rate for a 35 year-old: 129.5 bpm

If the input is:

17

the output is:

Invalid age.

Could not calculate heart rate info.

def get_age():
    age = int(input())
    if age < 18 or age > 75:
        raise ValueError("Invalid age.")
    # TODO: Raise exception for invalid ages
    return age

# TODO: Complete fat_burning_heart_rate() function
def fat_burning_heart_rate():
    age = get_age()
    heart_rate = (220 - age) * .70
    return heart_rate

user_input = ""
if __name__ == "__main__":
    try:
        age = get_age()
        heart_rate = fat_burning_heart_rate()
        print('Fat burning heart rate for a', age, 'year-old:', 
    heart_rate, 'bpm')
    except ValueError as excpt:
        print(excpt)
        print("Could not calculate heart rate info.")
    # TODO: Modify to call get_age() and fat_burning_heart_rate()
    #       and handle the exception
  

Program errors displayed here

Traceback (most recent call last):
  File "main.py", line 18, in <module>
    heart_rate = fat_burning_heart_rate()
  File "main.py", line 10, in fat_burning_heart_rate
    age = get_age()
  File "main.py", line 2, in get_age
    age = int(input())
EOFError: EOF when reading a line