ID 351176 - Disconnecting a node input via the API causes Mari to crash

Steps to reproduce

1) Open Example Head

2) In the Node Graph, select the Diffuse_Colour node

3) Run the script below in the Python Console:

node = mari.current.layer().layerNode()
node.setInputNode('Base', None)

In accordance with the Mari documentation, entering 'None' as the NodeToConnect should disconnect the input port.
Note: See setInputNode() for more information. 

4) Observe Mari crashes

Workaround
Unknown. 

Reproduced by support
Mari 4.0v4 - Win 7, CentOS 7
Mari 4.0v1
Mari 3,3v1 - Win 7, CentOS 7, OSX 10.12.6
Mari 3.2v1 - Win 7, CentOS 7

Earliest version tested
Mari 3.1v3  - Change in functionality. No attribute 'layerNode'.

Expected behaviour
You should be able to disconnect any of the existing inputs. In this instance, Mari crashes when attempting to disconnect Base, Over or Mask (all of the inputs to the Diffuse_Colour channel merge node).

Actual behaviour
Mari crashes whether an input exists or not.