in src/main/java/jetbrains/buildServer/investigationsAutoAssigner/heuristics/OneCommitterHeuristic.java [85:90]
private void ensureSameUsers(@Nullable User first,
@Nullable User second) {
if (first != null && second != null && !first.equals(second)) {
throw new HeuristicNotApplicableException("there are more then one TeamCity user");
}
}