Use ABC instead of ABCMeta (readability)

CHANGELOG.md

@@ -29,4 +29,4 @@ Fix bugs related to imports and `default_decoders`.
 refers to `DeterministicGlobalWorkspace`.
 
 # 0.4.0
-* Use ABCMeta for abstract methods.
+* Use ABC for abstract methods.

shimmer/modules/domain.py

@@ -8,7 +8,7 @@
 class DomainModule(pl.LightningModule):
     """
     Base class for a DomainModule.
-    We do not use ABCMeta here because some modules could be without encore or decoder.
+    We do not use ABC here because some modules could be without encore or decoder.
     """
 
     def encode(self, x: Any) -> torch.Tensor:

shimmer/modules/gw_module.py

@@ -1,4 +1,4 @@
-from abc import ABCMeta, abstractmethod
+from abc import ABC, abstractmethod
 from collections.abc import Iterable, Mapping
 
 import torch
@@ -79,7 +79,7 @@ def forward(self, x: torch.Tensor) -> tuple[torch.Tensor, torch.Tensor]:
         return self.layers(x), self.uncertainty_level.expand(x.size(0), -1)
 
 
-class GWModule(nn.Module, metaclass=ABCMeta):
+class GWModule(nn.Module, ABC):
     domain_descr: Mapping[str, DomainDescription]
     latent_dim: int
 

shimmer/modules/losses.py

@@ -1,4 +1,4 @@
-from abc import ABCMeta, abstractmethod
+from abc import ABC, abstractmethod
 from collections.abc import Mapping
 from typing import Literal
 
@@ -65,7 +65,7 @@ def contrastive_loss_with_uncertainty(
     return 0.5 * (ce + ce_t)
 
 
-class GWLosses(torch.nn.Module, metaclass=ABCMeta):
+class GWLosses(torch.nn.Module, ABC):
     """
     Base Abstract Class for Global Workspace (GW) losses. This module is used
     to compute the different losses of the GW (typically translation, cycle,

shimmer/modules/vae.py

@@ -1,5 +1,5 @@
 import math
-from abc import ABCMeta, abstractmethod
+from abc import ABC, abstractmethod
 from collections.abc import Sequence
 
 import torch
@@ -29,7 +29,7 @@ def gaussian_nll(
     )
 
 
-class VAEEncoder(nn.Module, metaclass=ABCMeta):
+class VAEEncoder(nn.Module, ABC):
     """
     Base class for a VAE encoder.
     """
@@ -48,7 +48,7 @@ def forward(
         ...
 
 
-class VAEDecoder(nn.Module, metaclass=ABCMeta):
+class VAEDecoder(nn.Module, ABC):
     """
     Base class for a VAE decoder.
     """