Hi

Today I cloned the repository and installed the package directly instead from PyPi.

After reopening nvim I noticed that nvim was very laggy in all python files.
I found out that the issue was with my snippet engine Ultisnips.
Deleting the package and reinstalling it from PyPi made the lag go away.

The version on PyPi is 4.3 and so I went through the git history to check where something significant changed.
I located the issue to be this PR #506.
This PR changes the num_to_str function to include a boolean check.
The helper function is used in the LegacyVim object's eval function here.
Browsing through the Ultisnips source code reveals that it uses vim.eval at many places.
Thus, this change is non-trivial in terms of Ultisnips performance.

I wonder what could be done to circument this issue?