[IMP] calendar: add helpers to mange virtual ids
[IMP] calendar: add helpers to mange virtual ids

ygol/odoo,hip-odoo/odoo,dfang/odoo,ygol/odoo,hip-odoo/odoo,ygol/odoo,hip-odoo/odoo,dfang/odoo,dfang/odoo,ygol/odoo,hip-odoo/odoo,dfang/odoo,dfang/odoo,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,dfang/odoo