unset a configuration value
            Parameters
           ==========
           name: the name of the value to unset (remove key in dictionary)
           quiet: disable verbose output if True (default is False)

def unset_config_value(self, name, quiet=False):
        """unset a configuration value
            Parameters
           ==========
           name: the name of the value to unset (remove key in dictionary)
           quiet: disable verbose output if True (default is False)
        """

        config_data = self._read_config_file()

        if name in config_data:

            del config_data[name]

            self._write_config_file(config_data)

            if not quiet:
                self.print_config_value(name, separator=' is now set to: ')