(a) All real property of a housing authority shall be exempt from levy and sale by virtue of an execution, and no execution or other judicial process shall issue against it, nor shall any judgment against the authority be a charge or lien upon its real property.
(b) The provisions of this section shall not apply to or limit the right of obligees to foreclose or otherwise enforce any mortgage of any authority or the right of obligees to pursue any remedies for the enforcement of any pledge or lien given by an authority on its rents, fees, or revenues.