Verify the completeness of the data.

        Raises:
            ValueError: When this chat is invalid.

def verify(self):
        """
        Verify the completeness of the data.

        Raises:
            ValueError: When this chat is invalid.
        """
        if any(not i for i in (self.chat_uid, self.module_id)):
            raise ValueError("Chat data is incomplete.")
        if not isinstance(self.chat_type, ChatType):
            raise ValueError("Invalid chat type.")
        if self.chat_type == ChatType.Group:
            if any(not isinstance(i, EFBChat) or not i.chat_type == ChatType.User for i in self.members):
                raise ValueError("The group has an invalid member.")
        if self.group is not None and (not isinstance(self.group, EFBChat) or
                                       not self.group.chat_type == ChatType.Group):
            raise ValueError("The member is in an invalid group.")