as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
write a python function that takes a number and returns the factorial of that number.
user
def factorial(num): 
  if num == 0: 
    return 1 
  else: 
    return num * factorial(num-1)
assistant