def set_value ( self, object, name, value ):
        cname = TraitsCache + name
        old   = object.__dict__.get( cname, Undefined )
        if value != old:
            object.__dict__[ cname ] = value
            object.trait_property_changed( name, old, value )

    #-- Private Methods --------------------------------------------------------
Sets the cached value of a property-based trait and fires the
dataset/ETHPy150Open enthought/traits/traits/trait_handlers.py/TraitType.set_value