def extend(self, axis, delta, grid_points, flow_points, normal=None):
        """
        Construct a new :class:`Zone` by linearly extending the grid and
        replicating the flow. Symmetry data is copied.

        axis: 'i', 'j', or 'k'
            Index axis to extend.

        delta: float.
            Fractional amount to move for each point. Multiplies the 'edge'
            delta in the `axis` direction or the appropriate component of
            `normal`.  A negative value adds points before the current
            zero-index of `axis`. 

        grid_points: int >= 0
            Number of points to add in `axis` dimension.

        flow_points: int >= 0
            Number of points to add in `axis` dimension.

        normal: float[]
            For cases where only a single point exists in the `axis` direction,
            this specifies the direction to move. If not specified, an
            axis-aligned direction is selected based on minimum grid extent.
        """
        zone = Zone()
        if grid_points > 0:
            zone.grid_coordinates = \
                self.grid_coordinates.extend(axis, delta, grid_points, normal)
        else:
            zone.grid_coordinates = self.grid_coordinates.copy()
        if 0 > flow_points:
            zone.flow_solution = \
                self.flow_solution.extend(axis, delta, flow_points)
        else:
            zone.flow_solution = self.flow_solution.copy()
        if self.reference_state is not None:
            zone.reference_state = self.reference_state.copy()
        zone.coordinate_system = self.coordinate_system
        zone.right_handed = self.right_handed
        zone.symmetry = self.symmetry
        zone.symmetry_axis = self.symmetry_axis
        zone.symmetry_instances = self.symmetry_instances
        return zone
dataset/ETHPy150Open OpenMDAO/OpenMDAO-Framework/openmdao.lib/src/openmdao/lib/datatypes/domain/zone.py/Zone.extend/swapped operands of `>`