Open ArcGIS Portal WebMap in ArcMap via ArcPy

[MarioNowak]

In the ArcGIS Online Portal, I can open a WebMap in ArcMap, which essentially downloads a mxd file.

Is there a function in ArcPy that do this task? 

What I want to do with ArcPy:

* Login to ArcGIS Portal

* Select a WebMap

* Download a WebMap as mxd file