You must make sure that Django is installed in the virtual environment. Then make sure you make pip install
within the same virtual environment.
For example, in your command interface, enter your virtual environment, I assume you are using virtualenv.
source tuvirtualenv/bin/activate
Now to be sure that Django is installed we will use pip freeze to see what things are installed in our environment.
pip freeze
We should show a list of applications installed in our virtual environment. With this you can check if pymdeco has been installed as well.