def validate ( self, object, name, value ):
        try:
            if issubclass( value, self.klass ):
                return value
        except:
            if (value is None) and (self._allow_none):
                return value

        self.error( object, name, value )
Validates that the value is a valid object instance.
dataset/ETHPy150Open enthought/traits/traits/trait_types.py/Type.validate