how to import a blender model and manipulate the imported model? I have a few vehicle blender model files and a ground blender model files separately. the project needs to use python to automatically create vehicle instances onto the ground blender model. To do that, i will need to find blender API to load the vehicle model to ground model through the code. 

On the blender api, I need find the 

bpy.ops.import_scene.obj(filepath=path, axis_forward='-Z', axis_up='Y', filter_glob="*.obj;*.mtl")  


but the API seems to only load the obj model instead of blender model. I want to use blender model is because it also has texture, loading obj model doesn't seem to have the texture loaded. (maybe this is wrong)
Look into bpy.ops.wm.link() and bpy.ops.wm.append(). This is how the GUI transfers objects across .blend files. (To find that out, I used the Python tooltips and hovered over the Link and Append buttons.)