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Including a module with "use" reads the module and makes it available to your program within its own namespace. By default, many modules will export symbols (variables, functions, methods, etc.) into the "main::" namespace. This allows you access to these symbols without prefixing them with their proper namespace. Specifying a list of symbols with the "use" statement overrides the choice of symbols to export. When this list is empty, no symbols are exported. The symbols are still accessible by prefixing them with the namespace of the module.