Error message when trying to initialize loader manager and run from mayapy.exe

When running the following code using mayapy.exe in batch mode and not in the maya gui it results in an error

import sgtk
engine = sgtk.platform.current_engine()
loader_app = engine.apps.get(“tk-multi-loader2”)
manager = loader_app.create_loader_manager()

   manager = loader_app.create_loader_manager()
  File "C:\Users\vineet.vijaykumar\AppData\Roaming\Shotgun\bundle_cache\sg\vineet\v369949\", line 89, in create_loader_manager
    return self._manager_class(self)
AttributeError: 'MultiLoader' object has no attribute '_manager_class'

running the code in maya script editor seems to work fine and I can execute manager actions once the manager object is initalized but for some reason it errors out in batch mode. Wondering if anyone has seen this error before and if there is any way around it