In optparse module - command line option parser, how to confirm if an option was not provided?
<p>From Python docs:</p>

<p>"Option.dest : If the option’s action implies writing or modifying a value somewhere, this tells optparse where to write it: dest names an attribute of the options object that optparse builds as it parses the command line."</p>

<p>Can we put some check on the name of the attribute (dest) to check if it's value was provided? Say, I want to perform some action to determine it's value when no value is provided for it in CLI, as I don't have a fixed default value.</p>

<p>Checking against 'None' does not work.</p>
