How do I move a sequencer clip that I've cut to a certain frame (python)

I have this code I’ve been trying to write all day
it seems I could usually move sequencer clip with a below code when I first bring it into the scene
But after I cut the clip it seems like no matter how I write this this function
I cant change the start frame of the clip while maintaining the length
If somebody could show me how to do that I would appreciate
it I’m using a slider to change the frame start value
that’s listed as as one of the two variables in the sets_frame_start function
thanks in advance for any help on this…

def set_frame_start(self, frame_start):
    selected = bpy.context.selected_objects
    if selected != None:
        active_object = bpy.context.active_object
        if active_object != None:
            mat = active_object.active_material
            if hasattr(mat, "node_tree"):
                myMaterial =
                myMaterial.use_nodes = True
                node_tree = myMaterial.node_tree
                node = node_tree.nodes.get("Image Texture")

                # Get the selected clip
                sequence_name = active_object.get("my_custom_property")
                sequence = bpy.context.scene.sequence_editor.sequences.get(sequence_name)

                # Move the clip and adjust its start and end frames
                sequence.frame_start = frame_start

                sequence.frame_final_end =  sequence.frame_start + sequence.frame_duration

                # Print variables

                if node != None:
                    node.image_user.frame_start = frame_start + 1

    return None