Python not configured for Tk

You need to have the Tk development files/headers available during pyenv install.

On Ubuntu (15.04) the following should provide them: sudo apt-get install tk-dev.

After this, pyenv install 3.4.3 (or pyenv install 2.7.10 etc) should pick it up and have support for Tk.

(Reference issue in pyenv)

This is a guide for Mac users,

1. Uninstall your python version. For example: pyenv uninstall 3.7.2
2. Install TK: brew install tcl-tk
3. Follow the post install steps and config tk:

export LDFLAGS="-L/usr/local/opt/tcl-tk/lib"
export CPPFLAGS="-I/usr/local/opt/tcl-tk/include"
export PATH=$PATH:/usr/local/opt/tcl-tk/bin

4. Reload your terminal session and make sure all settings above are correctly set
5. Install python: pyenv install 3.7.2

The TK should work now