FIFTH EDITION Learning Python Mark Lutz Beijing • Cambridge • Farnham • Köln • Sebastopol • Tokyo Learning Python, Fifth Edition by Mark Lutz Copyright © 2013 Mark Lutz. All rights reserved. Printed in the United States of America. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (). For more information, contact our corporate/institutional sales department: 800-998-9938 or corporate@. Editor: Rachel Roumeliotis Indexer: Lucie Haskins Production Editor: Christopher Hearse Cover Designer: Randy Comer Copyeditor: Rachel Monaghan Interior Designer: David Futato Proofreader: Julie Van Keuren Illustrator: Rebecca Demarest June 2013: Fifth Edition. Revision History for the Fifth Edition: 2013-06-07 First release See /catalog/errata.csp?isbn=9781449355739 for release details. Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. Learning Python, 5th Edition, the image of a wood rat, and related trade dress are trademarks of O’Reilly Media, Inc. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and O’Reilly Media, Inc., was aware of a trademark claim, the designations have been printed in caps or initial caps. While every precaution has been taken in the preparation of this book, the publisher and authors assume no responsibility for errors or omissions, or for damages resulting from the use of the information con- tained herein.