def get_command_class(self, command):
        """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.
        """
        klass = self.cmdclass.get(command)
        if klass:
            return klass

        for pkgname in self.get_command_packages():
            module_name = "{}.{}".format(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)
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.
        
product/gradle-plugin/src/main/python/setuptools/_distutils/dist.py