Delegation is most important for odoo module, it is the third inheritance mechanism which provides more flexibility (it can be altered at runtime) but less power: using the _inherits a model delegates the lookup of any field not found on the current model to "children" models. The delegation performes reference fields automatically set up on the parent model.
For example code is below.

class Child0(models.Model):
    _name = 'delegation.child0'

    field_0 = fields.Integer()

class Child1(models.Model):
    _name = 'delegation.child1'

    field_1 = fields.Integer()

class Delegating(models.Model):
    _name = 'delegation.parent'

    _inherits = {
        'delegation.child0': 'child0_id',
        'delegation.child1': 'child1_id',
    }

    child0_id = fields.Many2one('delegation.child0', required=True, ondelete='cascade')
    child1_id = fields.Many2one('delegation.child1', required=True, ondelete='cascade')
        record = env['delegation.parent'].create({
            'child0_id': env['delegation.child0'].create({'field_0': 0}).id,
            'child1_id': env['delegation.child1'].create({'field_1': 1}).id,
        })
        record.field_0
        record.field_1

And output will be- 0
1
and it's possible to write directly on the delegated field:

  record.write({'field_1': 4})