How flax classes are aware of their class variables?

[MiladInk]

Hi All! Happy to be part of community.
I have been using Flax for some time and there is one part that I am wondering how Flax implemented in Python.
The thing is when I write:
`class NN(nn.Module):
features: Sequence[int]

def setup(self):
self.layers = [nn.Dense(feat) for feat in self.features]then I can write
NN(features=[1, 3, 4] )
`
but it does not happen with Python usual classes. I am wondering how such a thing happens when we use nn.Module as a parent?

[marcvanzee]

Flax Modules are Python 3.7 dataclasses, which allows us to define the parameters this way. For more information, please see our documentation: https://flax.readthedocs.io/en/latest/flax.linen.html#flax.linen.Module