I really respect the settings of Takuya Matsuyama.
if you have an error such as this plugin requires python3 support
you may well run below
$ pip3 install --user pynvim
$ pip install --user pynvim (also in python2)
you should run below
$ cd
$ touch .cache/dein
$ curl https://raw.githubusercontent.com/Shougo/dein.vim/master/bin/installer.sh > installer.sh
# For example, we just use `~/.cache/dein` as installation directory
$ sh ./installer.sh ~/.cache/dein