Books

The digital revolution has knocked at the doors of the grand library. They are transitioning from conventional books to e-books. The cataloging system is managed by a Python program using a Book class which stores attributes like title, author, and publication_year.

Your task is to create a subclass named EBook, which inherits from the Book class. The EBook class should have additional attributes like file_size (in MB) and format (like 'PDF', 'EPUB', 'MOBI', etc.).

The Book class includes a __str__() method that returns a string including the title, author, and publication_year in the format: "Title: {title}, Author: {author}, Published: {publication_year}". You should override this __str__() method in the EBook class to return a string that includes the title, author, publication_year, file_size, and format in the following format: "Title: {title}, Author: {author}, Published: {publication_year}, Size: {file_size} MB, Format: {format}".