@Nullable
    private static PsiAssignmentExpression searchAssignmentExpression(@Nullable PsiElement anchor) {
      if (!(anchor instanceof PsiExpressionStatement)) return null;
      final PsiExpression anchorExpression = ((PsiExpressionStatement)anchor).getExpression();
      if (!(anchorExpression instanceof PsiAssignmentExpression)) return null;
      return (PsiAssignmentExpression)anchorExpression;
    }
@Nullable
    private static PsiAssignmentExpression searchAssignmentExpression(@Nullable PsiElement anchor)