Python has a “batteries included” philosophy. This is best seen through the sophisticated and robust capabilities of its larger packages. For example:? The xmlrpc.client and xmlrpc.server modules make implementing remote procedure calls into an almost trivial task. Despite the modules names, no direct knowledge or handling of XML is needed.? The email package is a library for managing email messages, including MIME and other RFC 2822-based message documents. Unlike smtplib and poplib which actually send and receive messages, the email package has a complete toolset for building or decoding complex message structures (including attachments) and for implementing internet encoding and header protocols.? The json package provides robust support for parsing this popular data interchange format. The csv module supports direct reading and writing of files in Comma-Separated Value format, commonly supported by databases and spreadsheets. XML processing is supported by the xml.etree.ElementTree, xml.dom and xml.sax packages. Together, these modules and packages greatly simplify data interchange between Python applications and other tools. Batteries Included表示什么意思？