def get_string(self, key, default=UndefinedKey):
        """Return string representation of value found at key

        :param key: key to use (dot separated). E.g., a.b.c
        :type key: basestring
        :param default: default value if key not found
        :type default: basestring
        :return: string value
        :type return: basestring
        """
        value = self.get(key, default)
        if value is None:
            return None

        string_value = unicode(value)
        if isinstance(value, bool):
            string_value = string_value.lower()
        return string_value
Return string representation of value found at key

        :param key: key to use (dot separated). E.g., a.b.c
        :type key: basestring
        :param default: default value if key not found
        :type default: basestring
        :return: string value
        :type return: basestring