Two files that simulate a calculator WITH __name__ == '__main__'

calc.py

# This script simulates a primitve calculator
def multiply(num_1, num_2):
  """Returns the product of two numbers"""
  return num_1 * num_2

def add(num_1, num_2):
  """Returns the sum of two numbers"""
  return num_1 + num_2

def main():
  print('Calc.py was ran as a script!')
  result = multiply(3, 5)
  print(f'Here is your result {result}')

if __name__ == '__main__':
  main()

main.py

import calc
print('Calc.py was imported but not ran as a script!')