  Anomaly detection algorithms have been proved to be useful in the search of
new physics beyond the Standard Model. However, a prerequisite for using an
anomaly detection algorithm is that the signal to be sought is indeed
anomalous. This does not always hold true, for example when interference
between new physics and the Standard Model becomes important. In this case, the
search of new physics is no longer an anomaly detection. To overcome this
difficulty, we propose a nested anomaly detection algorithm, which appears to
be useful in the study of neutral triple gauge couplings at the CEPC, the ILC
and the FCC-ee. Our approach inherits the advantages of the anomaly detection
algorithm been nested, while at the same time, it is no longer an anomaly
detection algorithm. As a complement to anomaly detection algorithms, it can
achieve better results on problems that are no longer anomaly detection.
