def switch(
        cls, variable, custom=False
    ):  # pylint: disable=inconsistent-return-statements
        """
        Switch PyFunceble.CONFIGURATION variables to their opposite.

        :param variable:
            The variable name to switch.
            The variable should be an index our configuration system.
            If we want to switch a bool variable, we should parse
            it here.
        :type variable: str|bool

        :param custom:
            Let us know if have to switch the parsed variable instead
            of our configuration index.
        :type custom: bool

        :return:
            The opposite of the configuration index or the given variable.
        :rtype: bool

        :raises:
            :code:`Exception`
                When the configuration is not valid. In other words,
                if the PyFunceble.CONFIGURATION[variable_name] is not a bool.
        """

        if not custom:
            # We are not working with custom variable which is not into
            # the configuration.

            # We get the current state.
            current_state = dict.get(PyFunceble.CONFIGURATION, variable)
        else:
            # We are working with a custom variable which is not into the
            # configuration
            current_state = variable

        if isinstance(current_state, bool):
            # The current state is a boolean.

            if current_state:
                # The current state is equal to True.

                # We return False.
                return False

            # The current state is equal to False.

            # We return True.
            return True

        # The current state is not a boolean.

        # We set the message to raise.
        to_print = "Impossible to switch %s. Please post an issue to %s"

        # We raise an exception inviting the user to report an issue.
        raise Exception(
            to_print % (repr(variable), PyFunceble.LINKS["repo"] + "/issues.")
        )
Switch PyFunceble.CONFIGURATION variables to their opposite.

        :param variable:
            The variable name to switch.
            The variable should be an index our configuration system.
            If we want to switch a bool variable, we should parse
            it here.
        :type variable: str|bool

        :param custom:
            Let us know if have to switch the parsed variable instead
            of our configuration index.
        :type custom: bool

        :return:
            The opposite of the configuration index or the given variable.
        :rtype: bool

        :raises:
            :code:`Exception`
                When the configuration is not valid. In other words,
                if the PyFunceble.CONFIGURATION[variable_name] is not a bool.