Replacement of 20 asserts with exceptions (#24757)
* initial replacements of asserts with errors/exceptions
* replace assert with exception in generation, align and bart
* reset formatting change
* reset another formatting issue
* Apply suggestion
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
* don't touch this file
* change to 'is not False'
* fix type
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Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
