Why does my main program default to the except?

Question

Could you possibly check my syntax and tell me why the debugger skips my try statement and skips to the except.

book class:

class book(object):
    
    def _init_(self, title, author, numPages):
        if title is None:
            raise ValueError("invalid 'title' argument. please try again")
        if author is None:
            raise ValueError("invalid 'author' argument. please try again")
        if numPages <= 0:
            raise ValueError("invalid 'numPages' argument. please try again")
        
        self.title = title
        self.author = author
        self.numPages = numPages

main class:

from book import book

def printBook (b):
    if b is None:
        raise ValueError('invalid book argument')
    print (b.author + ": " + b.title + "n" +" Number of page: " + b.numPages )

if __name__ == '__main__':
    try: 
        b1 = book("The Eye of the World", "Robert Jordan", 685)
        b2 = book("The Heir of Novron", "Michael J. Sullivan", 932)
        
        printBook(b1)
        printBook(b2)
        
    except:
        print("ERROR: INVALID BOOK")

Asked By: Justin Moon

||

Source

Answer 1

There are at least 2 mistakes:

Constructor is called __init__ as jonsharpe already mentioned
you need str() for concatenation of ints and string. So you need to modify your print function:
```
print (b.author + ": " + b.title + "n" +" Number of page: " + str(b.numPages) )
```

Answered By: Peter Parker

Why does my main program default to the except?

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