Python – Flask-Migrate command ‘flask db init’ can’t find app file

Firstly, I'm following the Python Flask tutorial posted here: https://scotch.io/tutorials/build-a-crud-web-app-with-python-and-flask-part-one .

Everything was working smoothly up to the 'Migration' section where executing:

$ flask db init
… failed with the following error:
Usage: flask db init [OPTIONS]
Error: The file/path provided (run) does not appear to exist.  Please verify the path is correct.  If app is not on PYTHONPATH, ensure the extension is .py
I know the $FLASK_APP env variable is set because this command executes fine:
$ flask run
Can anyone suggest why this executes fine when running the app, but not when trying to create the migration repository?
The closest I can find elsewhere on the subject is here: Flask can't find app file, but pre-pending with python -m isn't working in either case for me here.
Related Solutions
Python – Using Pip to install packages to Anaconda Environment

For others who run into this situation, I found this to be the most straightforward solution:
Run conda create -n venv_name and conda activate venv_name, where venv_name is the name of your virtual environment.
Run conda install pip. This will install pip to your venv directory.
Find your anaconda directory, and find the actual venv folder. It should be somewhere like /anaconda/envs/venv_name/.
Install new packages by doing /anaconda/envs/venv_name/bin/pip install package_name.
This should now successfully install packages using that virtual environment's pip!