def create_shell(shell=None, **kwargs):
if not shell:<EOL><INDENT>shell = config.default_shell<EOL>if not shell:<EOL><INDENT>from rez.system import system<EOL>shell = system.shell<EOL><DEDENT><DEDENT>from rez.plugin_managers import plugin_manager<EOL>return plugin_manager.create_instance('<STR_LIT>', shell, **kwargs)<EOL>
Returns a Shell of the given type, or the current shell type if shell
    is None.