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
create a function, "factorial_of()," that takes in an integer and returns its factorial.
user
def factorial_of(n):
    """this function takes in a integer 'n' and returns its factorial.
    
    args: 
        n (int): the number to calculate the factorial of
      
    returns: 
        int: the calculated factorial of 'n'
    """
    if n == 0:
        return 1
    else:
        return n * factorial_of(n-1)
assistant