Set the value of one option.
        
        # TODO/FIXME 
            * add force/hide argument
            * add default argument
            * remove methods force option value
            * remove change_option_default
            
        :param opt_name: option name
        :type opt_name: str
        :param value: the new value
        :param parse: if True the value is converted from string to the correct type
        :type parse: bool

def set_option_value(self, opt_name, value, parse=False):
        """ Set the value of one option.
        
        # TODO/FIXME 
            * add force/hide argument
            * add default argument
            * remove methods force option value
            * remove change_option_default
            
        :param opt_name: option name
        :type opt_name: str
        :param value: the new value
        :param parse: if True the value is converted from string to the correct type
        :type parse: bool
        
        """
        if not self.has_option(opt_name):
            raise ValueError("Unknow option name (%s)" % opt_name)
        self._options[opt_name].set(value, parse=parse)