Brew cleanup unable to remove old python

Question

Due to long travel, I did not get a chance to update or upgrade brew for a long time and now when I run brew update or brew cleanup I get the following message:

 $ brew cleanup
 Removing: /usr/local/Cellar/python/3.6.5... (3,196 files, 75MB)
 Error: Could not remove /usr/local/Cellar/python/3.6.5! Check its 
 permissions.

Is it safe to remove the 3.6.5 subdirectory from /usr/local/Cellar/python/3.6.5 as root and then do a brew cleanup again?

EDIT: Output of brew doctor

Your system is ready to brew.

Output of brew cleanup -vd

<Long output suppressed>   
==> This operation has freed approximately 75MB of disk space.

Answer 1

For this particular error

Because homebrew is suggesting the problem could be a permission issue you can try to solve it by restoring the proper ownership on the Homebrew Cellar directory.

sudo chown -R your_user_name /usr/local/Cellar/

or a more general solution

sudo chown -R "$USER" "$(brew --prefix)/Cellar"

It worth to remember you can use brew doctor to check your system for potential problems. Usually, ignore the warnings if any.