def get_true (self, key, default):
        """Return default element if key is not in the dict, or if self[key]
        evaluates to False. Useful for example if value is None, but
        default value should be an empty string.
        """
        if key not in self or not self[key]:
            return default
        return self[key]
Return default element if key is not in the dict, or if self[key]
        evaluates to False. Useful for example if value is None, but
        default value should be an empty string.