I have a custom module, where there is the class:

class sale_order(orm.Model):
    _inherit = 'sale.order'
..............................................

and another class:

class procurement_order(orm.Model):
    _inherit = "procurement.order"
..............................................

In the first class, for example, I have the method A. In the second one, the method B. How can I call the class A from the second class?