def __init__ ( self, trait = None, value = None, items = True, **metadata ):
        metadata.setdefault( 'copy', 'deep' )

        if isinstance( trait, SetTypes ):
            trait, value = value, set( trait )

        if value is None:
            value = set()

        self.item_trait = trait_from( trait )
        self.has_items  = items

        super( Set, self ).__init__( value, **metadata )
Returns a Set trait.
dataset/ETHPy150Open enthought/traits/traits/trait_types.py/Set.__init__