Update conformer with bug fixes.
This pull request **introduces 1 alert** and **fixes 2** when merging 58871c29e0990a1d316eecda9ad54c8a2fc23c10 into 203633d43fc997c2b7d089d94a0e113ebf2e0381 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-cb8227a1d7c811a936f38ca9ad1de026d5f9a1b6)

**new alerts:**

* 1 for Unused import

**fixed alerts:**

* 1 for Signature mismatch in overriding method
* 1 for Unused import > 
> 
> Could you revert the changes related to WER for the time being? That needs further discussion and is not necessary for bug fixes to Conformer model itself. Everything else related to conformer modules looks good to me.

Dropped that part but keep in mind that predictions_len comes from the output of the decoder. So if a model return that, it is used otherwise it is ignored. For some models like encoder/decoder with cross attention it should return None for instance. So it would just used for the models who returns the valid length of their outputs. > Dropped that part but keep in mind that predictions_len comes from the output of the decoder. So if a model return that, it is used otherwise it is ignored. For some models like encoder/decoder with cross attention it should return None for instance. So it would just used for the models who returns the valid length of their outputs.

All CTC based encoders return this length value, which would affect WER calculations wrt QuartzNet/Jasper as well. In the future, yes we can add this but there needs to be a special flag passed by only certain models - say Attention based models - which then submits the lengths for masking to the WER decoding. This is so that unrelated models such as QN/Jasper are not affected by this masking during wer. This pull request **fixes 2 alerts** when merging 11007248b28ccfad5e63b1a8e75956a35abbb5c7 into 21a55cdb7a2150114a28b84e9521920ceb56181b - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-267ca61f8e59ff7c78621434ff4ba2b5c4e7af12)

**fixed alerts:**

* 1 for Signature mismatch in overriding method
* 1 for Unused import This pull request **fixes 2 alerts** when merging 206fe29d77d91cb3495cee49915e1528a0bea652 into 2ced0eaca3e8a781aee48548914c610c432764e3 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-c6b142b51b4a9a190753cdbb46e9c83eea3f0867)

**fixed alerts:**

* 1 for Signature mismatch in overriding method
* 1 for Unused import