Fix expiresIn (convert String to Int)
diff --git a/lib/src/handle_access_token_response.dart b/lib/src/handle_access_token_response.dart
index 370ffcb..ba78d94 100644
--- a/lib/src/handle_access_token_response.dart
+++ b/lib/src/handle_access_token_response.dart
@@ -68,9 +68,18 @@
     }
 
     var expiresIn = parameters['expires_in'];
-    if (expiresIn != null && expiresIn is! int) {
-      throw FormatException(
-          'parameter "expires_in" was not an int, was "$expiresIn"');
+    if (expiresIn != null) {
+      if (expiresIn is String) {
+        try {
+          expiresIn = double.tryParse(expiresIn).toInt();
+        } catch (e) {
+          throw FormatException(
+              'parameter "expires_in" was not an int, and given string cant not be parsed to int : "$expiresIn"');
+        }
+      } else if (expiresIn is! int) {
+        throw FormatException(
+            'parameter "expires_in" was not an int, was of type ${expiresIn.runtimeType.toString()} value : "$expiresIn"');
+      }
     }
 
     for (var name in ['refresh_token', 'id_token', 'scope']) {