pytest errors fixed

Author: prishajain1

src/maxdiffusion/generate_wan.py

@@ -17,7 +17,8 @@
 import time
 import os
 import subprocess
-from maxdiffusion.checkpointing.wan_checkpointer import WanCheckpointer2_1, WanCheckpointer2_2
+from maxdiffusion.checkpointing.wan_checkpointer_2_1 import WanCheckpointer2_1
+from maxdiffusion.checkpointing.wan_checkpointer_2_2 import WanCheckpointer2_2
 from maxdiffusion import pyconfig, max_logging, max_utils
 from absl import app
 from maxdiffusion.utils import export_to_video