@Nullable
      private static ComplexAssignment extract(PsiStatement @NotNull [] statements, @NotNull PsiVariable nullCheckedExtremum) {
        if (statements.length != 2) return null;
        PsiStatement first = statements[0];
        PsiStatement second = statements[1];
        ComplexAssignment assignment = extract(first, second, nullCheckedExtremum);
        if (assignment != null) return assignment;
        return extract(second, first, nullCheckedExtremum);
      }
@Nullable
      private static ComplexAssignment extract(PsiStatement @NotNull [] statements, @NotNull PsiVariable nullCheckedExtremum)