def __setitem__(self, name, value):
    if (('members' in self.__dict__) and (name in self.members)):
        if (self.members[name] is value):
            return
        else:
            raise AlfredError(f'{name} is a member of {self}. The name is reserved.')
    else:
        raise KeyError(f"{name} not found in members of {self}. You can use square bracket syntax only for changing existing pages, not for adding new ones. Please use the augmented assignment operator '+=' for this purpose.")
def __setitem__(self, name, value):
    if (('members' in self.__dict__) and (name in self.members)):
        if (self.members[name] is value):
            return
        else:
            raise AlfredError(f'{name} is a member of {self}. The name is reserved.')
    else:
        raise KeyError(f"{name} not found in members of {self}. You can use square bracket syntax only for changing existing pages, not for adding new ones. Please use the augmented assignment operator '+=' for this purpose.")