class UserModel:
    def __init__ (self, id, context):
        self.id=id 
        self.context=context
        
    def getID(self):
        return self.id
    
    def getContext(self):
        return self.context
        
    def setContext(self,context):
        self.context=context
        _doContextCallbacks()
        
    def __str__(self):
        return self.id
       
	def addUserListener(self, func):
		self.callbacks[func] = 1

    def delUserListener(self, func):
		del self.callback[func]

    def _doContextCallbacks(self):
		for func in self.callbacks:
			func(self)