Q: zsh: command not found: flask I am unable to proceed with the command flask db init
from flask import Flask, render_template, request, redirect, url_for, jsonify
from flask_sqlalchemy import SQLAlchemy
import sys
from flask_migrate import Migrate
from flask_cli import FlaskCLI
from flask_cli import FlaskGroup

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgres://postgres@localhost:5432/todoapp'
db = SQLAlchemy(app)

migrate = Migrate(app, db)

class Todo(db.Model):
    __tablename__ = 'todos'
    id = db.Column(db.Integer, primary_key=True)
    description = db.Column(db.String(), nullable=False)

    def __repr__(self):
        return f'<Todo {self.id} {self.description}>'

db.create_all() 

@app.route('/')
def index():
    return render_template('index.html', data=Todo.query.all())

if __name__ == '__main__':
    app.run(debug=True)  

When I put the command pip3 list, this is result below:
Package            Version
------------------ -------
alembic            1.3.3  
appnope            0.1.0  
astroid            2.2.5  
attrs              19.1.0 
backcall           0.1.0  
bleach             3.1.0  
Click              7.0    
decorator          4.4.0  
defusedxml         0.6.0  
entrypoints        0.3    
Flask              1.1.1  
Flask-Alembic      2.0.1  
Flask-CLI          0.4.0  
Flask-Migrate      2.5.2  
Flask-MySQLdb      0.2.0  
Flask-SQLAlchemy   2.4.1  
Flask-WTF          0.14.2 
ipykernel          5.1.2  
ipython            7.8.0  
ipython-genutils   0.2.0  
ipywidgets         7.5.1  
isort              4.3.21 
itsdangerous       1.1.0  
jedi               0.15.1 
Jinja2             2.10.1 
jsonschema         3.0.2  
jupyter            1.0.0  
jupyter-client     5.3.1  
jupyter-console    6.0.0  
jupyter-core       4.5.0  
lazy-object-proxy  1.4.2  
Mako               1.1.1  
MarkupSafe         1.1.1  
mccabe             0.6.1  
mistune            0.8.4  
mysql              0.0.2  
mysqlclient        1.4.6  
nbconvert          5.6.0  
nbformat           4.4.0  
notebook           6.0.1  
pandocfilters      1.4.2  
parso              0.5.1  
passlib            1.7.2  
pexpect            4.7.0  
pickleshare        0.7.5  
pip                20.0.2 
prometheus-client  0.7.1  
prompt-toolkit     2.0.9  
ptyprocess         0.6.0  
pygame             1.9.6  
Pygments           2.4.2  
pylint             2.3.1  
pyrsistent         0.15.4 
python-dateutil    2.8.0  
python-editor      1.0.4  
pyzmq              18.1.0 
qtconsole          4.5.4  
Send2Trash         1.5.0  
setuptools         45.1.0 
six                1.12.0 
SQLAlchemy         1.3.13 
terminado          0.8.2  
testpath           0.4.2  
tornado            6.0.3  
traitlets          4.3.2  
typed-ast          1.4.0  
uWSGI              2.0.18 
wcwidth            0.1.7  
webencodings       0.5.1  
Werkzeug           0.16.0 
wheel              0.33.1 
widgetsnbextension 3.5.1  
wrapt              1.11.2 
WTForms            2.2.1 

And my python library site packages path is
/Users/kurosaki/Library/Python/3.8/lib/python/site-packages/

I have already tried python3 -m flask run 
which resulted in 

pkg_resources.DistributionNotFound: The 'alembic>=0.7' distribution
  was not found and is required by the application

I need help to proceed with flask command on the terminal.

A: I have the answer even if I am using python 3.8 or python 3.7
I have to use
python3 -m flask db init

so, in every flask command, I have to put 

python3 -m

before it

A: You may not be running an instance of your flask application. It may require this first
export FLASK_APP=app.py

Once you have a flask application instance, perform your database initialisations
