def area(width, length):
    print(f"Area of a {width} * {length} rectangle: {width * length}")
    #   The print statement is an example of 'side effect': action other than the return value. Side effects should be avoided as much as possible.
    
area(5,6)
area(7,10)

#   A better version: no side effect and use the return statement. It is also more general and useful.

def area2(width, length):
    return width * length
    
print(f"area2(5,6): {area2(5,6)}")
print(f"area2(7,2*4+2): {area2(7,2*4+2)}")
    
width_1 = 5
length_1 = 6
print(f"Area of a {width_1} * {length_1} rectangle: {area2(width_1, length_1)}")

width_2 =  7
length_2 = 10

print(f"Sum of the areas of the two rectangles: {area2(width_1, length_1) + area2(width_2, length_2)}")

def hello(name):
    """
    hello takes a name as a parameter and prints a greeting.
    """
    print(f"Hello, {name}!")
    print("Nice to meet you.") 
    
hello('Bun')
hello('Jane')