def enable_output_port(self, port_name):
        # Don't reset existing values, it screws up the caching.
        if port_name not in self.outputPorts:
            self.set_output(port_name, None)
Set an output port to be active to store result of computation
dataset/ETHPy150Open VisTrails/VisTrails/vistrails/core/modules/vistrails_module.py/Module.enable_output_port