Calling a method in a different class python

Question

I performed the function to move the points in the rectangle and the values returns none and none for both points. I do not want to return the value when the method in point is preferred, is there another option.

class Point:

    def move(self, dx, dy):
        '''(Point,number,number)->None
        changes the x and y coordinates by dx and dy'''
        self.x += dx
        self.y += dy

class Rectangle:

     def move(self, dx, dy):
        '''(Rectangle, number, number) -> None
        changes the x and y coordinates by dx and dy'''
        self.bottom_left = self.bottom_left.move(dx, dy)
        self.top_right = self.top_right.move(dx, dy)

Answer 1

There's no need to assign the result back to the point; Point.move modifies its argument directly, rather than returning a new Point object.

class Rectangle:
    def move(self, dx, dy):
        self.bottom_left.move(dx, dy)
        self.top_right.move(dx, dy)

Answer 2

In the rectangle class, if you set the corners with

self.corner = point.move(dx, dy)

the function Point.move() will need to return something, otherwise None is returned by default. You can remedy this by returning self for the Point.move

class Point(object):

    def __init__(self, x, y):
        self.x = x
        self.y = y

    def move(self, dx, dy):
        '''(Point,number,number)->None
        changes the x and y coordinates by dx and dy'''
        self.x += dx
        self.y += dy
        return self

That solves the problem without changing the Rectangle code. You could also do

class Rectangle(object):

    def __init__(self, top_right, bottom_left):
        self.top_right = Point(*top_right)
        self.bottom_left = Point(*bottom_left)

    def move(self, dx, dy):
        '''(Rectangle, number, number) -> None
        changes the x and y coordinates by dx and dy'''
        self.bottom_left.move(dx, dy)
        self.top_right.move(dx, dy)

which is probably a little better, but the first example explains why you were getting None.