Warnings when running IPython

[evandrix]

/usr/local/lib/python3.8/site-packages/traitlets/config/loader.py:795: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if len(key) is 1:
/usr/local/lib/python3.8/site-packages/traitlets/config/loader.py:804: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if len(key) is 1:

[Carreau]

THat has been fixed in master some time ago, thanks for the report.