Hi, I've been using the network modules to build azure network environments - vnets, subnets, route tables etc, but I'm getting a spurious error when using the SubnetRouteTableAssociation resource. I wont include my code here, as the example itself on the pulumi gives the same error also, even when my stack file has no additional variables. The code I'm using is directly copied from https://www.pulumi.com/docs/reference/pkg/azure/network/subnetroutetableassociation/ and the error I'm getting is 'error: Exception calling application: 'NoneType' object has no attribute 'islower'' Has anyone seen this before?