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Sometimes when running error into your code, they won't be syntax errors.

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instead they will be errors that don't show up until you try to run the code.

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We call these runtime errors.

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And we got some examples here.

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Let's make a working copy of this mvc errors.py, and we'll call

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this mvc-working.py.

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Open up that working copy and here we have demonstration file of a mvc model.

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mvc stands for Model View Controller, and if we run this and look at the output,

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you'll see that things aren't quite okay in the first forest here.

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So couple of places we have this bound method being printed out

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and that is not necessarily what we are looking for.

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So let's see we can hunt this bound.

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It says bound method Duck.feathers, bound method Person.feathers,

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bound method Dog.feathers.

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And so here is the feathers method. This gets inherited. We have Duck, Person

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and Dog and these are all inherit animal actions and the animal actions has

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the method feathers.

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So like it's inherited into these different classes, and that's getting

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printed out some place.

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So when we see this string in Python that says bound method blah, blah, blah,

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that means that you are trying to print a method, rather than calling it in.

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It usually means missed parenthesis.

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That's the most common thing here.

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And so Ecllipse is actually helping me here. Because I put my cursor on

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feathers up here, it's highlighting all the places where it sees the word

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feathers, and so this is jumping out at me here, and you'll notice that it's

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missing the parenthesis.

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So if I go ahead and put those parenthesis in, see I was printing the method

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instead of calling the method and printing what it returns.

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So if I save that and run it, now we don't get that error any more.

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And we have quack, the duck has no feathers, the person imitates a duck, and I am

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going to just say, "wait a minute, the duck has no feathers?" Ducks have feathers.

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And I know that I typed in feathers for the duck.

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See, the duck has gray and white feathers, and so why is it printing it this way?

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Well, you'll notice that the feathers method cause doAction for feathers and what

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doAction does is it looks for the strings with the action, and so the strings is

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defined in each of these animals.

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So I have strings here, strings there.

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So this is where strings are defined and it's looking for feathers, which is spelled wrong.

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And if I correct that spelling and save that and run it

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and we will look at our result here,

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we now see that the duck has gray and white feathers

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So often times it's a typo like that and these kind of things can be hard to find.

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The trick is to go through the code, to follow the execution path of the code,

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and to say if this gets called by that, that gets called by this, this is the

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way that's supposed to work and just take your time and be patient and try not

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get flummoxed by the error.

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I like to say the computers have infinite patience.

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It will sit there and stare at you with the error for as long as it takes.

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The trick is for you to try and gain as much as patience as the computer has in

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order to be able to find the errors.

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So often times these things just take patience, but the methodology is to go

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through the execution of the code and to look at all of the pieces that are

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supposed to fit together and try and find out piece that's not fitting together

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the way that it is supposed to.