import bpy
cameras = {}
scene = bpy.context.scene
frame = scene.frame_current - 1

# new frame
scene.frame_set(1 + frame)
# new frame
scene.frame_set(2 + frame)
# new frame
scene.frame_set(3 + frame)
# new frame
scene.frame_set(4 + frame)
# new frame
scene.frame_set(5 + frame)
# new frame
scene.frame_set(6 + frame)
# new frame
scene.frame_set(7 + frame)
# new frame
scene.frame_set(8 + frame)
# new frame
scene.frame_set(9 + frame)
# new frame
scene.frame_set(10 + frame)
# new frame
scene.frame_set(11 + frame)
# new frame
scene.frame_set(12 + frame)
# new frame
scene.frame_set(13 + frame)
# new frame
scene.frame_set(14 + frame)
# new frame
scene.frame_set(15 + frame)
# new frame
scene.frame_set(16 + frame)
# new frame
scene.frame_set(17 + frame)
# new frame
scene.frame_set(18 + frame)
# new frame
scene.frame_set(19 + frame)
# new frame
scene.frame_set(20 + frame)
# new frame
scene.frame_set(21 + frame)
# new frame
scene.frame_set(22 + frame)
# new frame
scene.frame_set(23 + frame)
# new frame
scene.frame_set(24 + frame)
# new frame
scene.frame_set(25 + frame)
# new frame
scene.frame_set(26 + frame)
# new frame
scene.frame_set(27 + frame)
# new frame
scene.frame_set(28 + frame)
# new frame
scene.frame_set(29 + frame)
# new frame
scene.frame_set(30 + frame)
# markers