Virtual environment in python, mkvirtualenv: command not found?

Question

linux

Installed python 3.7 (everything as root)

# apt-get install build-essential checkinstall
# apt-get install libreadline-gplv2-dev libncursesw5-dev libssl-dev
# apt-get install libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-dev libffi-dev

# wget https://www.python.org/ftp/python/3.7.3/Python-3.7.3.tgz
# tar xvf Python-3.7.3.tgz
# cd Python-3.7.3
# ./configure --enable-optimizations --enable-loadable-sqlite-extensions
# sudo make altinstall

Installed the virtualenvwrapper virtual environment

# python3.7 -m pip install virtualenvwrapper

# export VIRTUALENVWRAPPER_PYTHON=/usr/local/bin/python3.7
# export WORKON_HOME=~/venv

# . /usr/local/bin/virtualenvwrapper.sh

restarted bash
# exec bash
I'm trying to create a virtual environment, but it says that there is no such command?! :(

# mkvirtualenv --python=/usr/local/bin/python3.7 virtualenvname
mkvirtualenv: command not found

What have I done wrong?