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Hello Tiago,
your new module would have many2one field of same model to make parent and child relation same as product.category has parent_id many2one of product.category model.
define _rec_name as new compute field which compute and store hierarchy name.
please have a look following _compute_complete_name method which depends on name and parent_id


class ProductCategory(models.Model):
    _name = "product.category"
    _description = "Product Category"
    _parent_name = "parent_id"
    _parent_store = True
    _rec_name = 'complete_name'
    _order = 'complete_name'

    name = fields.Char('Name', index=True, required=True)
    complete_name = fields.Char(
        'Complete Name', compute='_compute_complete_name', recursive=True,store=True)
    parent_id = fields.Many2one('product.category', 'Parent Category', index=True, ondelete='cascade')
    parent_path = fields.Char(index=True)
    child_id = fields.One2many('product.category', 'parent_id', 'Child Categories')

    @api.depends('name', 'parent_id.complete_name')
    def _compute_complete_name(self):
        for category in self:
            if category.parent_id:
                category.complete_name = '%s / %s' % (category.parent_id.complete_name, category.name)
            else:
                category.complete_name = category.name
Let us know if you still need any help on this, 
Thanks,

Thanks & Regards,
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