Python version 3.6 
 Flask version 0.12.2 
 tried to run a development server using Flask-CLi, but it was unsuccessful anyway. 
  
 
can be started in the following ways:
if __name__ == "__main__":
    app.run() Python version 3.6 
 Flask version 0.12.2 
 tried to run a development server using Flask-CLi, but it was unsuccessful anyway. 
  
 
can be started in the following ways:
if __name__ == "__main__":
    app.run()the environment variable FLASK_APP was not found.
I remember that set in Powershell just defines a variable, not an environment variable.
 try  $env:FLASK_APP = "dispatch.py"  
 is set FLASK_APP=dispatch.py 
 "=" with no spaces on either side 
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