I cannot import something from transformers

Hi, when I run the following code:

from transformers import PegasusTokenizer, PegasusXForConditionalGeneration

I get the following error:

ImportError: cannot import name 'PegasusXForConditionalGeneration' from 'transformers' (/data1/app/data_dir/code-envs/python/python37_NLP_ssc/lib/python3.7/site-packages/transformers/__init__.py)

In my environment, transformers==4.20.1 & torch==1.12.0
I’ve seen many posts using this same question framework, but they each seem to have solutions unique to what they were importing. Please advise