diff --git a/Casbin/Abstractions/Evaluation/IExpressionHandler.cs b/Casbin/Abstractions/Evaluation/IExpressionHandler.cs
index a3188f89..299e69de 100644
--- a/Casbin/Abstractions/Evaluation/IExpressionHandler.cs
+++ b/Casbin/Abstractions/Evaluation/IExpressionHandler.cs
@@ -1,17 +1,14 @@
 using System;
-using Casbin.Caching;
-using Casbin.Effect;
 using Casbin.Model;
 
 namespace Casbin.Evaluation;
 
 public interface IExpressionHandler
 {
-    public IExpressionCachePool Cache { get; set; }
-
     public void SetFunction(string name, Delegate function);
 
-    public bool Invoke<TRequest, TPolicy>(in EnforceContext context, string expressionString, in TRequest request, in TPolicy policy)
+    public bool Invoke<TRequest, TPolicy>(in EnforceContext context, string expressionString, in TRequest request,
+        in TPolicy policy)
         where TRequest : IRequestValues
         where TPolicy : IPolicyValues;
 }
diff --git a/Casbin/Caching/ExpressionCache.cs b/Casbin/Caching/ExpressionCache.cs
index 3ee5a3b7..fb70c7d0 100644
--- a/Casbin/Caching/ExpressionCache.cs
+++ b/Casbin/Caching/ExpressionCache.cs
@@ -1,29 +1,11 @@
 using System;
-using System.Collections.Generic;
-using DynamicExpresso;
+using System.Collections.Concurrent;
 
 namespace Casbin.Caching;
 
-internal class ExpressionCache : IExpressionCache<Lambda>
-{
-    private readonly Dictionary<string, Lambda> _cache = new();
-
-    public bool TryGet(string expressionString, out Lambda lambda)
-    {
-        return _cache.TryGetValue(expressionString, out lambda);
-    }
-
-    public void Set(string expressionString, Lambda lambda)
-    {
-        _cache[expressionString] = lambda;
-    }
-
-    public void Clear() => _cache.Clear();
-}
-
 internal class ExpressionCache<TFunc> : IExpressionCache<TFunc> where TFunc : Delegate
 {
-    private readonly Dictionary<string, TFunc> _cache = new();
+    private readonly ConcurrentDictionary<string, TFunc> _cache = new();
 
     public bool TryGet(string expressionString, out TFunc func)
     {
diff --git a/Casbin/Caching/ExpressionCachePool.cs b/Casbin/Caching/ExpressionCachePool.cs
index 950da817..6f195b92 100644
--- a/Casbin/Caching/ExpressionCachePool.cs
+++ b/Casbin/Caching/ExpressionCachePool.cs
@@ -1,36 +1,12 @@
 using System;
-using System.Collections.Generic;
-using DynamicExpresso;
+using System.Collections.Concurrent;
+using System.Threading;
 
 namespace Casbin.Caching;
 
 public class ExpressionCachePool : IExpressionCachePool
 {
-    private readonly Dictionary<Type, IExpressionCache> _cachePool = new();
-
-    public void SetLambda(string expression, Lambda lambda)
-    {
-        Type type = typeof(Lambda);
-        if (_cachePool.TryGetValue(type, out IExpressionCache cache) is false)
-        {
-            cache = new ExpressionCache();
-            _cachePool[type] = cache;
-        }
-        var cacheImpl = (ExpressionCache) cache;
-        cacheImpl.Set(expression, lambda);
-    }
-
-    public bool TryGetLambda(string expression, out Lambda lambda)
-    {
-        Type type = typeof(Lambda);
-        if (_cachePool.TryGetValue(type, out IExpressionCache cache) is false)
-        {
-            lambda = default;
-            return false;
-        }
-        var cacheImpl = (ExpressionCache) cache;
-        return cacheImpl.TryGet(expression, out lambda);
-    }
+    private ConcurrentDictionary<Type, IExpressionCache> _cachePool = new();
 
     public void SetFunc<TFunc>(string expression, TFunc func) where TFunc : Delegate
     {
@@ -53,15 +29,14 @@ public bool TryGetFunc<TFunc>(string expression, out TFunc func) where TFunc : D
             cache = new ExpressionCache<TFunc>();
             _cachePool[type] = cache;
         }
+
         var cacheImpl = (IExpressionCache<TFunc>)cache;
         return cacheImpl.TryGet(expression, out func);
     }
 
     public void Clear()
     {
-        foreach (IExpressionCache cache in _cachePool.Values)
-        {
-            cache?.Clear();
-        }
+        ConcurrentDictionary<Type, IExpressionCache> cachePool = new ConcurrentDictionary<Type, IExpressionCache>();
+        Interlocked.Exchange(ref _cachePool, cachePool);
     }
 }
diff --git a/Casbin/Casbin.csproj b/Casbin/Casbin.csproj
index 7f14b426..0b17105d 100644
--- a/Casbin/Casbin.csproj
+++ b/Casbin/Casbin.csproj
@@ -47,46 +47,46 @@
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net7.0'">
-    <PackageReference Include="DynamicExpresso.Core" Version="2.11.0"/>
+    <PackageReference Include="DynamicExpresso.Core" Version="2.12.0"/>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="7.0.0-preview.1.22076.8"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net6.0'">
-    <PackageReference Include="DynamicExpresso.Core" Version="2.11.0"/>
+    <PackageReference Include="DynamicExpresso.Core" Version="2.12.0"/>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net5.0'">
-    <PackageReference Include="DynamicExpresso.Core" Version="2.11.0"/>
+    <PackageReference Include="DynamicExpresso.Core" Version="2.12.0"/>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="5.0.0"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
-    <PackageReference Include="DynamicExpresso.Core" Version="2.11.0"/>
+    <PackageReference Include="DynamicExpresso.Core" Version="2.12.0"/>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.22"/>
     <PackageReference Include="IsExternalInit" Version="1.0.2" PrivateAssets="all"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.1'">
-    <PackageReference Include="DynamicExpresso.Core" Version="2.11.0"/>
+    <PackageReference Include="DynamicExpresso.Core" Version="2.12.0"/>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0"/>
     <PackageReference Include="IsExternalInit" Version="1.0.2" PrivateAssets="all"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
-    <PackageReference Include="DynamicExpresso.Core" Version="2.11.0"/>
+    <PackageReference Include="DynamicExpresso.Core" Version="2.12.0"/>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0"/>
     <PackageReference Include="IsExternalInit" Version="1.0.2" PrivateAssets="all"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net462'">
-    <PackageReference Include="DynamicExpresso.Core" Version="2.11.0"/>
+    <PackageReference Include="DynamicExpresso.Core" Version="2.12.0"/>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0"/>
     <PackageReference Include="IsExternalInit" Version="1.0.2" PrivateAssets="all"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
-    <PackageReference Include="DynamicExpresso.Core" Version="2.10.0"/>
+    <PackageReference Include="DynamicExpresso.Core" Version="2.12.0"/>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0"/>
     <PackageReference Include="IsExternalInit" Version="1.0.2" PrivateAssets="all"/>
   </ItemGroup>
diff --git a/Casbin/Evaluation/ExpressionHandler.cs b/Casbin/Evaluation/ExpressionHandler.cs
index 939cdcbd..8c0a5818 100644
--- a/Casbin/Evaluation/ExpressionHandler.cs
+++ b/Casbin/Evaluation/ExpressionHandler.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Threading;
 using Casbin.Caching;
 using Casbin.Model;
@@ -10,9 +9,13 @@ namespace Casbin.Evaluation;
 
 internal class ExpressionHandler : IExpressionHandler
 {
-    public IExpressionCachePool Cache { get; set; } = new ExpressionCachePool();
     private readonly FunctionMap _functionMap = FunctionMap.LoadFunctionMap();
+    private IExpressionCachePool _cachePool = new ExpressionCachePool();
+#if !NET452
+    private readonly Interpreter _interpreter;
+#else
     private Interpreter _interpreter;
+#endif
 
     public ExpressionHandler()
     {
@@ -24,6 +27,9 @@ public ExpressionHandler()
 
     public void SetFunction(string name, Delegate function)
     {
+#if !NET452
+        _interpreter.SetFunction(name, function);
+#else
         List<Identifier> identifiers = new();
         bool exist = false;
         foreach (var identifier in _interpreter.Identifiers)
@@ -46,34 +52,42 @@ public void SetFunction(string name, Delegate function)
         interpreter.SetIdentifiers(identifiers);
         interpreter.SetFunction(name, function);
         Interlocked.Exchange(ref _interpreter, interpreter);
-        Cache.Clear();
+#endif
+        ExpressionCachePool cachePool = new ExpressionCachePool();
+        Interlocked.Exchange(ref _cachePool, cachePool);
     }
 
-    public bool Invoke<TRequest, TPolicy>(in EnforceContext context, string expressionString, in TRequest request, in TPolicy policy)
+    public bool Invoke<TRequest, TPolicy>(in EnforceContext context, string expressionString, in TRequest request,
+        in TPolicy policy)
         where TRequest : IRequestValues
         where TPolicy : IPolicyValues
     {
         if (context.View.SupportGeneric is false)
         {
-            if (Cache.TryGetFunc<Func<IRequestValues, IPolicyValues, bool>>(expressionString, out var func))
+            if (_cachePool.TryGetFunc<Func<IRequestValues, IPolicyValues, bool>>(expressionString,
+                    out Func<IRequestValues, IPolicyValues, bool> func))
             {
                 return func(request, policy);
             }
+
             func = CompileExpression<IRequestValues, IPolicyValues>(in context, expressionString);
-            Cache.SetFunc(expressionString, func);
+            _cachePool.SetFunc(expressionString, func);
             return func(request, policy);
         }
 
-        if (Cache.TryGetFunc<Func<TRequest, TPolicy, bool>>(expressionString, out var genericFunc) is not false)
+        if (_cachePool.TryGetFunc<Func<TRequest, TPolicy, bool>>(expressionString,
+                out Func<TRequest, TPolicy, bool> genericFunc) is not false)
         {
             return genericFunc(request, policy);
         }
+
         genericFunc = CompileExpression<TRequest, TPolicy>(in context, expressionString);
-        Cache.SetFunc(expressionString, genericFunc);
+        _cachePool.SetFunc(expressionString, genericFunc);
         return genericFunc(request, policy);
     }
 
-    private Func<TRequest, TPolicy, bool> CompileExpression<TRequest, TPolicy>(in EnforceContext context, string expressionString)
+    private Func<TRequest, TPolicy, bool> CompileExpression<TRequest, TPolicy>(in EnforceContext context,
+        string expressionString)
         where TRequest : IRequestValues
         where TPolicy : IPolicyValues
     {
@@ -89,6 +103,7 @@ private Interpreter CreateInterpreter()
         {
             interpreter.SetFunction(functionKeyValue.Key, functionKeyValue.Value);
         }
+
         return interpreter;
     }
 }
diff --git a/Casbin/Util/Utility.cs b/Casbin/Util/Utility.cs
index 9ea4add8..0743e708 100644
--- a/Casbin/Util/Utility.cs
+++ b/Casbin/Util/Utility.cs
@@ -21,10 +21,12 @@ internal static bool SetEquals(List<string> a, List<string> b)
             {
                 a = new List<string>();
             }
+
             if (b == null)
             {
                 b = new List<string>();
             }
+
             if (a.Count != b.Count)
             {
                 return false;
@@ -40,6 +42,7 @@ internal static bool SetEquals(List<string> a, List<string> b)
                     return false;
                 }
             }
+
             return true;
         }
     }