Checks if given key exists.

        :param section: Current section to check key in.
        :type section: unicode
        :param key: Current key to check.
        :type key: unicode
        :return: Key existence.
        :rtype: bool

def key_exists(self, section, key):
        """
        Checks if given key exists.

        :param section: Current section to check key in.
        :type section: unicode
        :param key: Current key to check.
        :type key: unicode
        :return: Key existence.
        :rtype: bool
        """

        LOGGER.debug("> Checking '{0}' key existence in '{1}' section.".format(key, section))

        self.__settings.beginGroup(section)
        exists = self.__settings.contains(key)
        self.__settings.endGroup()
        return exists