'Run the plugin. Must be implemented in subclasses.
It should perform whatever modifications are required
on the e-book and return the absolute path to the
modified e-book. If no modifications are needed, it should
return the path to the original e-book. If an error is encountered
it should raise an Exception. The default implementation
simply return the path to the original e-book. Note that the path to
the original file (before any file type plugins are run, is available as
self.original_path_to_file).
The modified e-book file should be created with the
:meth:`temporary_file` method.
:param path_to_ebook: Absolute path to the e-book.
:return: Absolute path to the modified e-book.'

def run(self, path_to_ebook):

    return path_to_ebook
