'Create a command string from the config command and optional args.'

def _command_str(self, args=None):

    command_str = config['play']['command'].get()
    if (not command_str):
        return util.open_anything()
    if args:
        if (ARGS_MARKER in command_str):
            return command_str.replace(ARGS_MARKER, args)
        else:
            return u'{}    {}'.format(command_str, args)
    else:
        return command_str.replace(('    ' + ARGS_MARKER), '')
