From 41227d193359d13efee32c94ae5a314d03615f32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C3=ABl=20Benesty?=
 <pommedeterresautee@users.noreply.github.com>
Date: Thu, 22 Aug 2019 03:42:37 +0200
Subject: [PATCH] fix #4764 (#4800)

check all classes in xgb.get.handle
---
 R-package/R/xgb.Booster.R | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/R-package/R/xgb.Booster.R b/R-package/R/xgb.Booster.R
index 6904219b5..3fc232edf 100644
--- a/R-package/R/xgb.Booster.R
+++ b/R-package/R/xgb.Booster.R
@@ -51,11 +51,13 @@ is.null.handle <- function(handle) {
 # Return a verified to be valid handle out of either xgb.Booster.handle or xgb.Booster
 # internal utility function
 xgb.get.handle <- function(object) {
-  handle <- switch(class(object)[1],
-    xgb.Booster = object$handle,
-    xgb.Booster.handle = object,
+  if (inherits(object, "xgb.Booster")) {
+    handle <- object$handle
+  } else if (inherits(object, "xgb.Booster.handle")) {
+    handle <- object
+  } else {
     stop("argument must be of either xgb.Booster or xgb.Booster.handle class")
-  )
+  }
   if (is.null.handle(handle)) {
     stop("invalid xgb.Booster.handle")
   }