def __call__(self, *optional):
        """
Returns the value of the reference. Any number of arguments can be passed, they will all be ignored.
        """
        if self.value is utils.NO_VALUE:
            raise Exception("Trying to read Ref('{0}') before assignment".format(self.name))

        return self.value
def __call__ ( self , * optional ) : if self . value is utils . NO_VALUE : raise Exception ( "Trying to read Ref('{0}') before assignment" . format ( self . name ) ) return self . value
Returns the value of the reference. Any number of arguments can be passed, they will all be ignored.