m.name, where m is a module and name accesses
a name defined in m's symbol table. Module attributes can be
assigned to. (Note that the import statement is not, strictly
spoken, an operation on a module object; import foo does not
require a module object named foo to exist, rather it requires
an (external) definition for a module named foo
somewhere.)
A special member of every module is __dict__.
This is the dictionary containing the module's symbol table.
Modifying this dictionary will actually change the module's symbol
table, but direct assignment to the __dict__ attribute is not
possible (i.e., you can write m.__dict__['a'] = 1, which
defines m.a to be 1, but you can't write m.__dict__ = {}.
Modules are written like this: <module 'sys'>.