Hello to all ! 

I am trying to use a custom indicator class in Alpha framework and load history data to warmup the indicators.


However I am getting the runtime error : 

Runtime Error: Trying to retrieve an element from a collection using a key that does not exist in that collection throws a KeyError exception. To prevent the exception, ensure that the key exist in the collection and/or that collection is not empty. KeyError : (<QuantConnect.Symbol object at 0x7f7c9c8d6390>,) (Open Stacktrace)

Any ideas where that might come from?

Is the implementation ok apart from that?


Thank you!