write_epub swallows IOError

The write_epub function, which is visibly the main function to create a EPUB file and which is used in the main example for the package, swallows IOError.

ebooklib/ebooklib/epub.py

Lines 1745 to 1748 in d4febc0

    
           try: 
        
               epub.write() 
        
           except IOError: 
        
               pass

This seems dangerous, or at the very least strange, since the caller for such a function would expect to be notified of such an error, and generally swallowing exceptions is a bad practice. Right now the function fails silently.

Very good point. This is just wrong. When it comes to exceptions probably the whole system when it comes to read/write should be overlooked and more custom exceptions should be introduced.