title: How to change the text "optional arguments" in argparse
body: <p>For some reason I do not use positional arguments in my program but accept "optional" arguments only, controlling whether an argument is truly optional by facilities like <code>narg='?'</code> or <code>action='store_true'</code>. Thus the "optional arguments" in the help text will be misleading. Can I display it simply as "arguments"? Thank you.</p>