Given an optparse.Option, returns a two-tuple of the option's variable name
    and default value.

def get_option_default(option):
    """
    Given an optparse.Option, returns a two-tuple of the option's variable name
    and default value.
    
    """
    return (
        option.dest, 
        None if option.default is optparse.NO_DEFAULT else option.default,
    )