Set camera position of all active render windows

def camera_position(self, camera_location):
        """ Set camera position of all active render windows """
        if camera_location is None:
            return

        if isinstance(camera_location, str):
            camera_location = camera_location.lower()
            if camera_location == 'xy':
                self.view_xy()
            elif camera_location == 'xz':
                self.view_xz()
            elif camera_location == 'yz':
                self.view_yz()
            elif camera_location == 'yx':
                self.view_xy(True)
            elif camera_location == 'zx':
                self.view_xz(True)
            elif camera_location == 'zy':
                self.view_yz(True)
            return

        if isinstance(camera_location[0], (int, float)):
            return self.view_vector(camera_location)

        # everything is set explicitly
        self.camera.SetPosition(camera_location[0])
        self.camera.SetFocalPoint(camera_location[1])
        self.camera.SetViewUp(camera_location[2])

        # reset clipping range
        self.ResetCameraClippingRange()
        self.camera_set = True