1. override_create_function

             class your_model(models.Model):
                _name='your.model'

                # Override Create Function
                @api.model
                def create(self,values):
                    # your logic goes here
                    override_create = super(your_model,self).create(values)
                    return override_create

            

eg:

            record = self.env['your.model'].create({
              'name': 'Example'
            })

2. override_write_function

            class your_model(models.Model):
                _name='your.model'    

                # Override Write Function
                @api.multi
                def write(self,values):
                    # your logic goes here
                    override_write = super(your_model,self).write(values)
                    return override_write

            

eg:

            record_ids = self.env['your.model'].search([('name', '=', 'Example')])
            for record in record_ids:
            record.write({
                'some_field': 'some_description'
            })

  

3. override_unlink_function

            class your_model(models.Model):
                _name='your.model'    
                
                #Override Unlink Function
                @api.multi
                def unlink(self,values):
                    #your logic goes here
                    override_unlink = super(your_model,self).unlink()
                    return override_unlink