'Check if current session has write privileges to the hosts file.
.. 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):

    self._writable = CommonUtil.check_privileges()[1]
    if (not self._writable):
        self.messagebox('Please    check    if    you    have    writing\nprivileges    to    the    hosts    file!', 1)
        exit()
