OMAHA  —  An Omaha landlord group is trying to prevent the city’s new rental registrations and inspections program from taking effect.  The Metropolitan Omaha Property Owners Association filed the lawsuit against the city of Omaha last week.  The City Council approved an ordinance earlier this year that requires landlords to register their properties and increases inspections of problem properties.  The property owners association says that the ordinance violates and bypasses a consent decree between the city of Omaha and the association.