def rectangle_default(length=7, width=4):
    """
    7. Function with more than one default input arguments
    This function demonstrates how a function handles more than one input 
    arguments and returns multiple outputs
    This function calculates the area and perimeter of a rectangle
    length: the length of a rectangle, default value is set to 7
    width: the width of a rectangle, default value is set to 4
    area  : the area of the square, must be a positive number
    perimeter: the perimeter of the square, must be a positive number
    """
    area = length * width
    perimeter = 2 * (length + width)
    return area, perimeter