nemo2 peft merge

[HuiyingLi]

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Collection: [Note which collection this PR will affect]

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[github-actions]

This PR is stale because it has been open for 14 days with no activity. Remove stale label or comment or update or this will be closed in 7 days.

[github-actions]

beep boop 🤖: 🙏 The following files have warnings. In case you are familiar with these, please try helping us to improve the code base.

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Your code was analyzed with PyLint. The following annotations have been identified:

************* Module nemo.collections.llm.peft.api
nemo/collections/llm/peft/api.py:35:0: C0116: Missing function or method docstring (missing-function-docstring)
************* Module nemo.collections.llm.peft.lora
nemo/collections/llm/peft/lora.py:133:0: C0301: Line too long (121/119) (line-too-long)
nemo/collections/llm/peft/lora.py:50:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/llm/peft/lora.py:73:0: C0115: Missing class docstring (missing-class-docstring)
nemo/collections/llm/peft/lora.py:104:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/collections/llm/peft/lora.py:116:0: C0116: Missing function or method docstring (missing-function-docstring)

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Your code has been rated at 9.67/10

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Thank you for improving NeMo's documentation!

[cuichenx]

small suggestion but otherwise LGTM

[cuichenx]

This function is a little long, could you break it into multiple sub functions for readability?
maybe 1) setup trainer 2) load model 3) merge (this is already compartmentalized so no need to change this) 4) save weights