Example of defining and calling functions in Python
        
        # A function without any input parameters
        #   that does not return data.
        def greeting():
            print("Hola")
        
        # A function with a single input parameter
        #   we expect to be a string that does not
        #   return data.
        def person_greeting(name):
            print("Welcome, " + name)
        
        # A function to calculate the distance between two points.
        #   We expect four integers total to represent the x, y values
        #   of each point and we return the calculated distance. 
        def calc_distance(point1_x, point1_y, point2_x, point2_y):
            # distance formula
            √((x2-x1)^2 + (y2-y1)^2)
            x = (point2_x - point1_x) ** 2
            y = (point2_y - point1_y) ** 2
            
            # Return the distance
            return (x + y) ** 0.5
        
        # Function calls
        greeting()
        person_greeting("Sam")
        person_greeting("Sally")
        
        # Variables for each of the x, y coordinates
        x1 = 10
        y1 = 30
        x2 = 5
        y2 = 7
        
        # Holds the result of the distance calculation
        point_distance = calc_distance(x1, y1, x2, y2)
        
        # Display the value to the screen
        print(point_distance)