I have an object a that inherits from object b
 class b(models.Model):
    x = fields.Char(string="x")
    y = fields.Char(string="y")
 class a(models.Model):
    _inherit = ['b']
    @api.model 
    def method(self, cr, uid, context=None): 
        valueofx=self.x 
        valueofy=self.y
I want to access to a value field of the class b from class a
I'm using this syntax..
     valueofx=self.x
     valueofy=self.y
The value of x and y is null / None. What's wrong ?
