private boolean isMapGetArgument(PsiReferenceExpression arg) {
      PsiExpressionList argList = tryCast(PsiUtil.skipParenthesizedExprUp(arg.getParent()), PsiExpressionList.class);
      if (argList == null || argList.getExpressionCount() != 1) return false;
      PsiMethodCallExpression call = tryCast(argList.getParent(), PsiMethodCallExpression.class);
      if (!MAP_GET.test(call)) return false;
      PsiExpression qualifier = call.getMethodExpression().getQualifierExpression();
      return EquivalenceChecker.getCanonicalPsiEquivalence().expressionsAreEquivalent(myMapReference, qualifier);
    }
private boolean isMapGetArgument(PsiReferenceExpression arg)