Use proper extended dictionary types for public properties (#9119)

Author: jhonabreul

Algorithm/QCAlgorithm.cs

@@ -58,6 +58,7 @@
 using Newtonsoft.Json;
 using QuantConnect.Securities.Index;
 using QuantConnect.Api;
+using Common.Util;
 
 namespace QuantConnect.Algorithm
 {
@@ -271,7 +272,7 @@ public SecurityManager Securities
         /// a security that is currently selected by the universe or has holdings or open orders.
         /// </summary>
         [DocumentationAttribute(SecuritiesAndPortfolio)]
-        public IReadOnlyDictionary<Symbol, Security> ActiveSecurities => UniverseManager.ActiveSecurities;
+        public ReadOnlyExtendedDictionary<Symbol, Security> ActiveSecurities => UniverseManager.ActiveSecurities;
 
         /// <summary>
         /// Portfolio object provieds easy access to the underlying security-holding properties; summed together in a way to make them useful.
@@ -914,7 +915,7 @@ public decimal GetParameter(string name, decimal defaultValue)
         /// Gets a read-only dictionary with all current parameters
         /// </summary>
         [DocumentationAttribute(ParameterAndOptimization)]
-        public IReadOnlyDictionary<string, string> GetParameters()
+        public ReadOnlyExtendedDictionary<string, string> GetParameters()
         {
             return _parameters.ToReadOnlyExtendedDictionary();
         }

AlgorithmFactory/Python/Wrappers/AlgorithmPythonWrapper.cs

@@ -682,7 +682,7 @@ public void OnEndOfTimeStep()
         /// <summary>
         /// Gets a read-only dictionary with all current parameters
         /// </summary>
-        public IReadOnlyDictionary<string, string> GetParameters() => _baseAlgorithm.GetParameters();
+        public ReadOnlyExtendedDictionary<string, string> GetParameters() => _baseAlgorithm.GetParameters();
 
         /// <summary>
         /// Gets the parameter with the specified name. If a parameter with the specified name does not exist,

Common/Interfaces/IAlgorithm.cs

@@ -430,7 +430,7 @@ InsightManager Insights
         /// <summary>
         /// Gets a read-only dictionary with all current parameters
         /// </summary>
-        IReadOnlyDictionary<string, string> GetParameters();
+        ReadOnlyExtendedDictionary<string, string> GetParameters();
 
         /// <summary>
         /// Gets the parameter with the specified name. If a parameter with the specified name does not exist,

Common/Securities/UniverseManager.cs

@@ -41,7 +41,7 @@ public class UniverseManager : BaseExtendedDictionary<Symbol, Universe, Concurre
         /// Read-only dictionary containing all active securities. An active security is
         /// a security that is currently selected by the universe or has holdings or open orders.
         /// </summary>
-        public IReadOnlyDictionary<Symbol, Security> ActiveSecurities => this
+        public ReadOnlyExtendedDictionary<Symbol, Security> ActiveSecurities => this
             .SelectMany(ukvp => ukvp.Value.Members.Select(mkvp => mkvp.Value))
             .DistinctBy(s => s.Symbol)
             .ToReadOnlyExtendedDictionary(s => s.Symbol);
@@ -153,4 +153,4 @@ protected virtual void OnCollectionChanged(UniverseManagerChanged e)
             CollectionChanged?.Invoke(this, e);
         }
     }
-}
+}