Hello,

I am trying to configure lean to work with my alpaca paper account using IEX. I am using the following config 

// defines the 'live-alpaca-iex' environment with IEX data feed
"live-alpaca-iex": {
"live-mode": true,

// real brokerage implementations require the BrokerageTransactionHandler
"live-mode-brokerage": "AlpacaBrokerage",
"data-queue-handler": "QuantConnect.ToolBox.IEX.IEXDataQueueHandler",
"setup-handler": "QuantConnect.Lean.Engine.Setup.BrokerageSetupHandler",
"result-handler": "QuantConnect.Lean.Engine.Results.LiveTradingResultHandler",
"data-feed-handler": "QuantConnect.Lean.Engine.DataFeeds.LiveTradingDataFeed",
"real-time-handler": "QuantConnect.Lean.Engine.RealTime.LiveTradingRealTimeHandler",
"transaction-handler": "QuantConnect.Lean.Engine.TransactionHandlers.BrokerageTransactionHandler",
"history-provider": "QuantConnect.ToolBox.IEX.IEXDataQueueHandler"
}

I receive the following error:

20200828 18:12:55.757 Trace:: LiveTradingDataFeed.GetDataQueueHandler(): will use QuantConnect.ToolBox.IEX.IEXDataQueueHandler
20200828 18:12:55.770 ERROR:: Engine.Run():  System.ComponentModel.Composition.Primitives.ComposablePartException: Cannot create an instance of type 'QuantConnect.ToolBox.IEX.IEXDataQueueHandler' because a constructor could not be selected for construction. Ensure that the type either has a default constructor, or a single constructor marked with the 'System.ComponentModel.Composition.ImportingConstructorAttribute'.

I'm just learning Lean and QuantConnect, so not sure if I've configured something wrong in config.json or in my python algo script. My script backtests fine, trying to move to testing in a paper account. 

Thanks in advance!