def del_restriction(self, command, user, event_types):
        """
        Removes restriction for given `command`.

        :param command: command on which the restriction should be removed.
        :type command: str
        :param user: username for which restriction should be removed.
        :type user: str
        :param event_types: types of events that should be removed from restriction.
        :type event_types: list
        """
        if user.lower() in self.commands_rights[command]:
            for event_type in event_types:
                try:
                    self.commands_rights[command][user.lower()].remove(event_type)
                except ValueError:
                    pass
            if not self.commands_rights[command][user.lower()]:
                self.commands_rights[command].pop(user.lower())
Removes restriction for given `command`.

        :param command: command on which the restriction should be removed.
        :type command: str
        :param user: username for which restriction should be removed.
        :type user: str
        :param event_types: types of events that should be removed from restriction.
        :type event_types: list