List Symbols = new List

List SymbolData = new List();

public override void Initialize()
SetStartDate(2009, 1, 1);

foreach (var symbol in Symbols)
AddSecurity(SecurityType.Forex, symbol, Resolution.Minute);

First day of using C# so i am sure i have made a silly mistake

"Backtest Error: Error initializing algorithm: Algorithm.AddSecurity(): The key already existed in the dictionary."