Load .blend file into Blender as Python Module I am using Blender as a Python module.
Now I am trying to load a scene into blender.
Unfurtunately the obvious function bpy.ops.wm.open_mainfile(filepath) does not work as expected.
The command fails saying:


  Calling operator "bpy.ops.wm.open_mainfile" error, expected a string
  enum in ('INVOKE_DEFAULT', 'INVOKE_REGION_WIN',
  'INVOKE_REGION_CHANNELS', 'INVOKE_REGION_PREVIEW', 'INVOKE_AREA',
  'INVOKE_SCREEN', 'EXEC_DEFAULT', 'EXEC_REGION_WIN',
  'EXEC_REGION_CHANNELS', 'EXEC_REGION_PREVIEW', 'EXEC_AREA',
  'EXEC_SCREEN')


Can anyone explain to me how to load an existing .blend file when blender is used as Pyhton module?
I found an answer to my question.

Problem was, that Python misinterpreted the passed argument filename.
Assigning the argument filename as follows fixes the error.

filepath = "path\to\file.blend"
bpy.ops.wm.open_mainfile(filepath=filepath)