Sets the Application verbosity level.

        :param verbosity_level: Verbosity level.
        :type verbosity_level: int
        :return: Method success.
        :rtype: bool

        :note: The expected verbosity level value is an integer between 0 to 4.

def set_verbosity_level(self, verbosity_level):
        """
        Sets the Application verbosity level.

        :param verbosity_level: Verbosity level.
        :type verbosity_level: int
        :return: Method success.
        :rtype: bool

        :note: The expected verbosity level value is an integer between 0 to 4.
        """

        self.__verbosity_level = verbosity_level
        foundations.verbose.set_verbosity_level(verbosity_level)
        self.__settings.set_key("Settings", "verbosity_level", verbosity_level)
        self.verbosity_level_changed.emit(verbosity_level)
        return True