How do I change the focal length of a camera with python? I am importing a VRML file using Blender command line. I need to change the focal length of the camera using the command line. 

How can I do that? I cannot find Python api for this.

Thanks.
It's in bpy.data.cameras['name of your camera object'].lens, or camera.angle (thanks @ideasman42).

Note that you must have a camera in the scene.