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Now that we've understood a little bit more about the terminal commands,

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let's come back to our Flask code and understand what the code is doing in a

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little bit more detail. For example, what is this name?

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Because we're creating this app from this Flask class

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and in order to initialize a new Flask application,

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there is only one required input,

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and that is the import_name.

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Let's go ahead and print it out.

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So if we print this __name__ and comment out the rest of our

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code and hit run,

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then you can see that it prints out __main_

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_.

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This name is one of the special attributes that's built into Python.

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At any given point,

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you could tap into the name to find out what is the current class, function,

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method, or descriptor's name.

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And when we get main, what it's telling us is

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basically we're executing the code in a particular module.

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So that means it's run as a script or from an interactive prompt,

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but it's not run from an imported module.

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It gives us this code here, if the name is equal to main,

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then execute something only if it's run as a script.

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This also takes us to

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one of the common ways that you'll see people run Flask apps.

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You'll see if __name__ is double equal to _

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_main__ as a string,

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so exactly what was printed just now when we printed out this name,

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well, if this is the case,

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then that means we're running the code from within this current file.

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We're running hello.py. So in that case,

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we're going to tap into our app and we're going to call the run method.

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Now this app.run

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basically does exactly the same thing as when we went into the terminal and

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we said flask run. But notice when we say flask run,

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firstly, we have to provide the FLASK_APP environment variable

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and secondly, we have to stop the code using control + c

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instead of using our normal run and stop.

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But if we use app.run, we can now use our standard controls.

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So I can simply hit run to run this hello.py,

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and it will start serving up our Flask app at this address just as it did

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before, when we did flask run. And instead of using control + c to quit,

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we can simply use the stop to stop our Flask application,

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making it a lot easier.

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Basically by providing the name to Flask, Flask 

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will check that this is the current file where the app code is located.

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And we're not in fact using an imported module. For example,

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if I was to import the random module and I was to print the random.name,

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then you can see the first thing that gets printed is the name of that module.

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But the name that's printed from hello.py

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which is the file that's being run is simply __main__.

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So this basically denotes the file that is currently being run

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and you say, Run 'hello' Well then inside hello

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name is going to be equal to main.

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Right.