Deleting unconnected node results in traceback

[FreakTheMighty]

Traceback (most recent call last):
File "/PyNode/Nodes.py", line 185, in keyPressEvent
self.group().delete()
File "/PyNode/Nodes.py", line 68, in delete
conn.incommingNode.outputs.remove(self)
ValueError: list.remove(x): x not in list