(self, union, values=None)
:param union:      A SimUnion instance describing the type of this union
        :param values:      A mapping from union members to values
:param union:      A SimUnion instance describing the type of this union
        :param values:      A mapping from union members to values
: param union : A SimUnion instance describing the type of this union : param values : A mapping from union members to values
def __init__(self, union, values=None):
        """
        :param union:      A SimUnion instance describing the type of this union
        :param values:      A mapping from union members to values
        """
        self._union = union
        self._values = defaultdict(lambda: None, values or ())
def __init__ ( self , union , values = None ) : self . _union = union self . _values = defaultdict ( lambda : None , values or ( ) )