The yamlget.py file was changed in !3311 as part of making the
python code pylint and flake8 compliant. This omitted setting
'item' to 'item[key]' which caused the digdelv yaml tests to fail.
Also, the pretty printing is not really necessary, so remove
the "if key not in item; print error" logic.
(cherry picked from commit 464d0417d1)