class Observed(object):
    def register_observer(self,observer):
        self.observer=observer
    def notify(self):
        self.observer.update(self)
 
class Observer(object):
    def update(self,other):
        print(self,"gets that ",other," has moved")
        #decide what to do
        pass
 
 
class Something(Observer,Observed):
    def __init__(self,x,y):
        self.x=x
        self.y=y
        #super(Something,self).__init__()
    def move_to(self,x,y):
        self.x=x
        self.y=y
        self.notify()
    def update(self,other):
        super(Something,self).update(other)
        if other.x<self.x: self.move_to(self.x-1,self.y)# or whatever
 
o1=Something(1,2)
o2=Something(5,4)
 
o1.register_observer(o2)
o2.register_observer(o1)
o1.move_to(1,2)

info = {'x1': 123, 'y1': 456, 'x2: 789, 'y2': 012}
 

def getpos():
        r1 = x,y = 100,100
        r2 = x,y = 800,800

Traceback (most recent call last):
    r1.step(r2.getPos()[0],r2.getPos()[1])
AttributeError: r2 instance has no attribute 'getPos'

    def getpos(self):
        r1 = x,y = 100,100
        r2 = x,y = 800,800

r1.step(r2.getPos()[0],r2.getPos()[1])
TypeError: getPos() takes no arguments (1 given)

class RobotB:
    def getPos(self):
        self.r1 = x,y = 100,200
        self.r2 = x,y = 700,800
        return self.r1, self.r2
 
r2 = RobotB()
print r2.getPos()         # ((100, 200), (700, 800))
print r2.getPos()[1]      # (700, 800)
print r2.getPos()[1][0]   # 700