how can i select 2 markers using python? i made a small python script, it creates 2 markers see below.
All i want is to be able to select 2 markers as we can do on screen

Also this script flips the coding text pannel into graph editor
i wonder if it is possible to use the allready opened graph editor?

ob = bpy.context.active_object
frame_num = 30

bpy.context.scene.frame_set(frame_num)
selected = bpy.context.selected_objects
scene = bpy.context.scene

bpy.context.area.type = 'GRAPH_EDITOR'
#add marker
bpy.ops.marker.add()
bpy.ops.marker.rename(name= "start" )

frame_end = frame_num + 20

bpy.context.scene.frame_set(frame_end)

bpy.ops.marker.add()
bpy.ops.marker.rename(name= "end" )
bpy.ops.marker.select()
bpy.context.scene.frame_set(frame_num)
bpy.ops.marker.select(extend=True )    #it doesnt work to add to marker selection
Can do this without the operators

import bpy
from bpy import context

scene = context.scene

start_marker = scene.timeline_markers.new("start") # make a new marker
start_marker.frame = scene.frame_start # set a frame
start_marker.select = True # set selected
end_marker = scene.timeline_markers.new("end")
end_marker.frame = scene.frame_end
end_marker.select = True

# get a marker
marker = scene.timeline_markers.get("start")
if marker:
    print(marker.name, marker.frame, marker.select)