Cannot instantiate a basic AllSet net

[peekxc]

When I do:

from topomodelx.nn.hypergraph.allset import AllSet
AllSet(1,1)

I get the (truncated) error:

...
--> [58] (...hypergraph/allset_layer.py:58) self.vertex2edge = AllSetBlock(...)
--> [231](...hypergraph/allset_layer.py:231) self.encoder = MLP(...)
--> [177](...hypergraph/allset_layer.py:177) layers.append(activation_layer(**params))
TypeError: 'NoneType' object is not callable

I tried supplying the sigmoid callable from torch.nn.functional to the mlp_activation argument but to no avail.