def __call__(self, key=None):
        """Returns the value of the result from calling the subroutine/function
        for the given key.
        """
        if self.utype == "function":
            return self.result["{}_o"]
        elif key is not None:
            return self.result[key]
        elif len(self.result) == 1:
            return list(self.result.values())[0]
        else:
            raise ValueError("Can't call result without a key for subroutines.")
def __call__ ( self , key = None ) : if self . utype == "function" : return self . result [ "{}_o" ] elif key is not None : return self . result [ key ] elif len ( self . result ) == 1 : return list ( self . result . values ( ) ) [ 0 ] else : raise ValueError ( "Can't call result without a key for subroutines." )
Returns the value of the result from calling the subroutine/function
        for the given key.