[error in unity]:An element with the same key already exists in the.dictionary

[Mrhaoyong]

When i read the tutorial  located in Leap_Motion_SDK_Win_3.1.3\LeapSDK\docs\Creating Your Own Hand Prefabs and operated  with it,occurred ArgumentException:
ArgumentException : An element with the same key already exists in the.dictionary

System.Collections.Generic.Dictionary`2[Leap.Unity.IHandModel,Leap.Unity.HandPool+ModelGroup].Add (Leap.Unity.IHandModel key, Leap.Unity.ModelGroup value) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/Dictionary.cs:404)
Leap.Unity.HandPool.Start () (at Assets/LeapMotion/Scripts/HandPool.cs:124)

Could any of you provide some suggestions?Thanks a lot! :relaxed:

[Joe_Ward]

Did you put the same hand model instance (in the scene hierarchy) in both the left and right slots in the hand pool?

You can use the same prefab if you drag it directly from the project panel, but if you put the hands in the scene first, you need separate instances for each hand.

[Mrhaoyong]

This error has disappeared already,after I did the operation you told me! Thank you very much!