As the code shown below, nn.ModuleList is not subclass of MutableSequence.
In [4]: from collections.abc import MutableSequence, Mapping

In [5]: import torch.nn as nn

In [6]: issubclass(nn.ModuleList, MutableSequence)
Out[6]: False

In [7]: issubclass(nn.ModuleDict, Mapping)
Out[7]: False

The source code of  ModuleList is
class ModuleList(Module):

Should we change the code to
class ModuleList(Module, MutableSequence):

Why or why not?