Feedforward is deprecated? Module needs shapes while binding. How can we do it without shapes?

[ghost]

I tried mx.mod.Module but it takes arguments such as data shapes when binding.
In feed forward we didn't need data shapes. What if i dont know the data shapes??
How can I incorporate Module?

Originally posted by @vizakshat in #5394 (comment)

[frankfliu]

@mxnet-label-bot add [question]

[chinakook]

Set some shape first, and it can be changed accord to the given data later.