'Check if current session is ran with root privileges.
.. note:: IF current session does not has the write privileges to the
hosts file of current system, a warning message box would popup.
.. note:: ALL operation would change the `hosts` file on current
system could only be done while current session has write
privileges to the file.'

def check_writable(self):

    writable = CommonUtil.check_privileges()[1]
    self._writable = writable
    if (not writable):
        self.warning_permission()
