'Return the class that implements the Distutils command named by
\'command\'.  First we check the \'cmdclass\' dictionary; if the
command is mentioned there, we fetch the class object from the
dictionary and return it.  Otherwise we load the command module
("distutils.command." + command) and fetch the command class from
the module.  The loaded class is also stored in \'cmdclass\'
to speed future calls to \'get_command_class()\'.
Raises DistutilsModuleError if the expected module could not be
found, or if that module does not define the expected class.'

def get_command_class(self, command):

    klass = self.cmdclass.get(command)
    if klass:
        return klass
    for pkgname in self.get_command_packages():
        module_name = ('%s.%s' % (pkgname, command))
        klass_name = command
        try:
            __import__(module_name)
            module = sys.modules[module_name]
        except ImportError:
            continue
        try:
            klass = getattr(module, klass_name)
        except AttributeError:
            raise DistutilsModuleError(("invalid    command    '%s'    (no    class    '%s'    in    module    '%s')" % (command, klass_name, module_name)))
        self.cmdclass[command] = klass
        return klass
    raise DistutilsModuleError(("invalid    command    '%s'" % command))
