title: Python Argparse - How can I add text to the default help message?
body: <p>I'm using python's argparse to handle parsing of arguments.
  I get a default help message structured like so:</p>
  
  <pre><code>usage: ProgramName [-h] ...
  
  Description
  
  positional arguments:
    ...
  
  optional arguments:
    -h, --help            show this help message and exit
    ...
  </code></pre>
  
  <p>What I want is to add an entire new section to this message, for example:</p>
  
  <pre><code>usage: ProgramName [-h] ...
  
  Description
  
  positional arguments:
    ...
  
  optional arguments:
    -h, --help            show this help message and exit
    ...
  
  additional information:
    This will show additional information relevant to the user.
    ....
  </code></pre>
  
  <p>Is there a way to achieve this behavior?
  A solution that is supported by both python 2.7 and 3.x is preferred.</p>
  
  <p>Edit:
  I would also rather have a solution that will add the new section / sections at the bottom of the help message.</p>