diff --git a/CR.Exceptions.AspNet.Tests/Component/LogLevelMapTests.cs b/CR.Exceptions.AspNet.Tests/Component/LogLevelMapTests.cs
index 80d9d0e..9a4c889 100644
--- a/CR.Exceptions.AspNet.Tests/Component/LogLevelMapTests.cs
+++ b/CR.Exceptions.AspNet.Tests/Component/LogLevelMapTests.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.AspNet.Mapping;
-using CR.Exceptions.Tests.Shared;
+using CR.Exceptions.Tests.Shared;
 using Microsoft.Extensions.Logging;
 
 namespace CR.Exceptions.AspNet.Tests.Component;
diff --git a/CR.Exceptions.AspNet.Tests/Component/StatusCodeMapTests.cs b/CR.Exceptions.AspNet.Tests/Component/StatusCodeMapTests.cs
index f2b0e92..eeba7b8 100644
--- a/CR.Exceptions.AspNet.Tests/Component/StatusCodeMapTests.cs
+++ b/CR.Exceptions.AspNet.Tests/Component/StatusCodeMapTests.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.AspNet.Mapping;
-using CR.Exceptions.Tests.Shared;
+using CR.Exceptions.Tests.Shared;
 using Microsoft.AspNetCore.Http;
 
 namespace CR.Exceptions.AspNet.Tests.Component;
diff --git a/CR.Exceptions.AspNet.Tests/Unit/LogLevelMapBuilderTests.cs b/CR.Exceptions.AspNet.Tests/Unit/LogLevelMapBuilderTests.cs
index 54e5334..63a2bca 100644
--- a/CR.Exceptions.AspNet.Tests/Unit/LogLevelMapBuilderTests.cs
+++ b/CR.Exceptions.AspNet.Tests/Unit/LogLevelMapBuilderTests.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.AspNet.Mapping;
-using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging;
 
 namespace CR.Exceptions.AspNet.Tests.Unit;
 
diff --git a/CR.Exceptions.AspNet.Tests/Unit/StatusCodeMapBuilderTests.cs b/CR.Exceptions.AspNet.Tests/Unit/StatusCodeMapBuilderTests.cs
index 1ad0d71..2c3e3f9 100644
--- a/CR.Exceptions.AspNet.Tests/Unit/StatusCodeMapBuilderTests.cs
+++ b/CR.Exceptions.AspNet.Tests/Unit/StatusCodeMapBuilderTests.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.AspNet.Mapping;
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
 
 namespace CR.Exceptions.AspNet.Tests.Unit;
 
diff --git a/CR.Exceptions.AspNet/CrExceptionHandler.cs b/CR.Exceptions.AspNet/CrExceptionHandler.cs
index ca3d52e..058aa8b 100644
--- a/CR.Exceptions.AspNet/CrExceptionHandler.cs
+++ b/CR.Exceptions.AspNet/CrExceptionHandler.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.AspNet.Mapping;
-using Microsoft.AspNetCore.Diagnostics;
+using Microsoft.AspNetCore.Diagnostics;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging;
diff --git a/CR.Exceptions.AspNet/Mapping/LogLevelMap.cs b/CR.Exceptions.AspNet/Mapping/LogLevelMap.cs
index 1ef880e..44b7057 100644
--- a/CR.Exceptions.AspNet/Mapping/LogLevelMap.cs
+++ b/CR.Exceptions.AspNet/Mapping/LogLevelMap.cs
@@ -1,9 +1,8 @@
-using CR.Exceptions.Mapping;
-using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging;
 using System.Collections.Frozen;
 using System.Diagnostics.CodeAnalysis;
 
-namespace CR.Exceptions.AspNet.Mapping;
+namespace CR.Exceptions.AspNet;
 
 public class LogLevelMap : TypeMap<LogLevel>
 {
diff --git a/CR.Exceptions.AspNet/Mapping/LogLevelMapBuilder.cs b/CR.Exceptions.AspNet/Mapping/LogLevelMapBuilder.cs
index 5660cb5..e158ca4 100644
--- a/CR.Exceptions.AspNet/Mapping/LogLevelMapBuilder.cs
+++ b/CR.Exceptions.AspNet/Mapping/LogLevelMapBuilder.cs
@@ -1,7 +1,6 @@
-using CR.Exceptions.Mapping;
-using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging;
 
-namespace CR.Exceptions.AspNet.Mapping;
+namespace CR.Exceptions.AspNet;
 
 public class LogLevelMapBuilder : MapBuilder<Type, LogLevel>
 {
diff --git a/CR.Exceptions.AspNet/Mapping/LogLevelMapBuilderExtensions.cs b/CR.Exceptions.AspNet/Mapping/LogLevelMapBuilderExtensions.cs
index 77a22ae..2253630 100644
--- a/CR.Exceptions.AspNet/Mapping/LogLevelMapBuilderExtensions.cs
+++ b/CR.Exceptions.AspNet/Mapping/LogLevelMapBuilderExtensions.cs
@@ -1,6 +1,6 @@
 using Microsoft.Extensions.Logging;
 
-namespace CR.Exceptions.AspNet.Mapping;
+namespace CR.Exceptions.AspNet;
 
 public static class LogLevelMapBuilderExtensions
 {
diff --git a/CR.Exceptions.AspNet/Mapping/StatusCodeMap.cs b/CR.Exceptions.AspNet/Mapping/StatusCodeMap.cs
index 50c85bc..f65f4e3 100644
--- a/CR.Exceptions.AspNet/Mapping/StatusCodeMap.cs
+++ b/CR.Exceptions.AspNet/Mapping/StatusCodeMap.cs
@@ -1,8 +1,7 @@
-using CR.Exceptions.Mapping;
-using System.Collections.Frozen;
+using System.Collections.Frozen;
 using System.Diagnostics.CodeAnalysis;
 
-namespace CR.Exceptions.AspNet.Mapping;
+namespace CR.Exceptions.AspNet;
 
 public class StatusCodeMap : TypeMap<int>
 {
diff --git a/CR.Exceptions.AspNet/Mapping/StatusCodeMapBuilder.cs b/CR.Exceptions.AspNet/Mapping/StatusCodeMapBuilder.cs
index 8db409e..7df2ff7 100644
--- a/CR.Exceptions.AspNet/Mapping/StatusCodeMapBuilder.cs
+++ b/CR.Exceptions.AspNet/Mapping/StatusCodeMapBuilder.cs
@@ -1,7 +1,6 @@
-using CR.Exceptions.Mapping;
-using System.Net;
+using System.Net;
 
-namespace CR.Exceptions.AspNet.Mapping;
+namespace CR.Exceptions.AspNet;
 
 public class StatusCodeMapBuilder : MapBuilder<Type, int>
 {
diff --git a/CR.Exceptions.AspNet/Mapping/StatusCodeMapBuilderExtensions.cs b/CR.Exceptions.AspNet/Mapping/StatusCodeMapBuilderExtensions.cs
index 597a311..9ec57a6 100644
--- a/CR.Exceptions.AspNet/Mapping/StatusCodeMapBuilderExtensions.cs
+++ b/CR.Exceptions.AspNet/Mapping/StatusCodeMapBuilderExtensions.cs
@@ -1,6 +1,6 @@
 using Microsoft.AspNetCore.Http;
 
-namespace CR.Exceptions.AspNet.Mapping;
+namespace CR.Exceptions.AspNet;
 
 public static class StatusCodeMapBuilderExtensions
 {
diff --git a/CR.Exceptions.AspNet/ServiceCollectionExtensions.cs b/CR.Exceptions.AspNet/ServiceCollectionExtensions.cs
index c5a2965..b0cdf9d 100644
--- a/CR.Exceptions.AspNet/ServiceCollectionExtensions.cs
+++ b/CR.Exceptions.AspNet/ServiceCollectionExtensions.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.AspNet.Mapping;
-using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace CR.Exceptions.AspNet;
 
diff --git a/CR.Exceptions.Tests.Shared/TestUnknownException.cs b/CR.Exceptions.Tests.Shared/TestUnknownException.cs
index e7d5a29..53b36ab 100644
--- a/CR.Exceptions.Tests.Shared/TestUnknownException.cs
+++ b/CR.Exceptions.Tests.Shared/TestUnknownException.cs
@@ -6,5 +6,5 @@ public sealed class TestUnknownException : CrException
 {
     private static readonly ImmutableArray<CrError> _errors = [new("TestUnknownCode", "TestUnknownMessage")];
 
-    public TestUnknownException() : base(_errors, "Test unknown exception message") { }
+    public TestUnknownException(Exception? innerException = null) : base(_errors, "Test unknown exception message", innerException) { }
 }
\ No newline at end of file
diff --git a/CR.Exceptions.Tests/Component/ExceptionFactoryTests.cs b/CR.Exceptions.Tests/Component/ExceptionFactoryTests.cs
index 0790f52..5c6c811 100644
--- a/CR.Exceptions.Tests/Component/ExceptionFactoryTests.cs
+++ b/CR.Exceptions.Tests/Component/ExceptionFactoryTests.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.Mapping;
-using CR.Exceptions.Tests.Shared;
+using CR.Exceptions.Tests.Shared;
 
 namespace CR.Exceptions.Tests.Component;
 
diff --git a/CR.Exceptions.Tests/Component/ExceptionTranslatorTests.cs b/CR.Exceptions.Tests/Component/ExceptionTranslatorTests.cs
index b2a3ffc..b5a35a2 100644
--- a/CR.Exceptions.Tests/Component/ExceptionTranslatorTests.cs
+++ b/CR.Exceptions.Tests/Component/ExceptionTranslatorTests.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.Mapping;
-using CR.Exceptions.Tests.Shared;
+using CR.Exceptions.Tests.Shared;
 
 namespace CR.Exceptions.Tests.Component;
 
@@ -50,7 +49,7 @@ public void Translate_ShouldThrow_WhenExceptionDoesNotExist()
     private static ExceptionTranslator GetDefaultTranslator()
     {
         return new ExceptionTranslatorBuilder()
-            .Map<TestInternalException>(() => new TestUnknownException())
+            .Map<TestInternalException>(ex => new TestUnknownException(ex))
             .Build();
     }
 }
\ No newline at end of file
diff --git a/CR.Exceptions.Tests/Unit/ExceptionFactoryBuilderTests.cs b/CR.Exceptions.Tests/Unit/ExceptionFactoryBuilderTests.cs
index fe13be2..741f98e 100644
--- a/CR.Exceptions.Tests/Unit/ExceptionFactoryBuilderTests.cs
+++ b/CR.Exceptions.Tests/Unit/ExceptionFactoryBuilderTests.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.Mapping;
-using CR.Exceptions.Tests.Shared;
+using CR.Exceptions.Tests.Shared;
 
 namespace CR.Exceptions.Tests.Unit;
 
diff --git a/CR.Exceptions.Tests/Unit/ExceptionTranslatorBuilderTests.cs b/CR.Exceptions.Tests/Unit/ExceptionTranslatorBuilderTests.cs
index 0bfa369..18531fd 100644
--- a/CR.Exceptions.Tests/Unit/ExceptionTranslatorBuilderTests.cs
+++ b/CR.Exceptions.Tests/Unit/ExceptionTranslatorBuilderTests.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.Mapping;
-using CR.Exceptions.Tests.Shared;
+using CR.Exceptions.Tests.Shared;
 
 namespace CR.Exceptions.Tests.Unit;
 
@@ -9,8 +8,8 @@ public sealed class ExceptionTranslatorBuilderTests
     public void Map_ShouldThrow_WhenDuplicateRegistered()
     {
         var builder = new ExceptionTranslatorBuilder()
-            .Map<TestInternalException>(() => new TestUnknownException());
+            .Map<TestInternalException>(ex => new TestUnknownException(ex));
 
-        Assert.ThrowsAny<ArgumentException>(() => builder.Map<TestInternalException>(() => new TestUnknownException()));
+        Assert.ThrowsAny<ArgumentException>(() => builder.Map<TestInternalException>(ex => new TestUnknownException(ex)));
     }
 }
\ No newline at end of file
diff --git a/CR.Exceptions/CrException.cs b/CR.Exceptions/CrException.cs
index 83ba31c..1f12fc6 100644
--- a/CR.Exceptions/CrException.cs
+++ b/CR.Exceptions/CrException.cs
@@ -1,5 +1,4 @@
-using CR.Exceptions.Extensions;
-using System.Collections.Immutable;
+using System.Collections.Immutable;
 
 namespace CR.Exceptions;
 
diff --git a/CR.Exceptions/Extensions/FuncExtensions.cs b/CR.Exceptions/Extensions/FuncExtensions.cs
deleted file mode 100644
index 12c1be1..0000000
--- a/CR.Exceptions/Extensions/FuncExtensions.cs
+++ /dev/null
@@ -1,15 +0,0 @@
-using System.Runtime.CompilerServices;
-
-namespace CR.Exceptions.Extensions;
-
-internal static class FuncExtensions
-{
-    extension<TResult>(Func<TResult> func)
-    {
-        public TResult ToResult([CallerArgumentExpression(nameof(func))] string? paramName = null)
-        {
-            ArgumentNullException.ThrowIfNull(func, paramName);
-            return func() ?? throw new NullReferenceException("delegate return null");
-        }
-    }
-}
\ No newline at end of file
diff --git a/CR.Exceptions/Extensions/ImmutableArrayExtensions.cs b/CR.Exceptions/Extensions/ImmutableArrayExtensions.cs
index 5b1a635..1de079b 100644
--- a/CR.Exceptions/Extensions/ImmutableArrayExtensions.cs
+++ b/CR.Exceptions/Extensions/ImmutableArrayExtensions.cs
@@ -1,7 +1,7 @@
 using System.Collections.Immutable;
 using System.Runtime.CompilerServices;
 
-namespace CR.Exceptions.Extensions;
+namespace CR.Exceptions;
 
 internal static class ImmutableArrayExtensions
 {
diff --git a/CR.Exceptions/Mapping/ExceptionFactory.cs b/CR.Exceptions/Mapping/ExceptionFactory.cs
index 579016c..e1b7913 100644
--- a/CR.Exceptions/Mapping/ExceptionFactory.cs
+++ b/CR.Exceptions/Mapping/ExceptionFactory.cs
@@ -1,16 +1,20 @@
-using CR.Exceptions.Extensions;
-using System.Collections.Frozen;
+using System.Collections.Frozen;
 using System.Diagnostics.CodeAnalysis;
 
-namespace CR.Exceptions.Mapping;
+namespace CR.Exceptions;
 
 public class ExceptionFactory : Map<string, Func<CrException>>
 {
     internal ExceptionFactory(FrozenDictionary<string, Func<CrException>> dictionary) : base(dictionary) { }
 
     public CrException Create(string code)
-        => GetValue(code).ToResult();
+        => ExecuteFactory(GetValue(code));
 
     public bool TryCreate(string code, [MaybeNullWhen(false)] out CrException exception)
-        => (exception = TryGetValue(code, out var factory) ? factory.ToResult() : null) != null;
+        => (exception = TryGetValue(code, out var factory) ? ExecuteFactory(factory) : null) != null;
+
+    private static CrException ExecuteFactory(Func<CrException> factory)
+    {
+        return factory() ?? throw new InvalidOperationException($"{nameof(factory)} '{factory.Method.Name}' returned null.");
+    }
 }
\ No newline at end of file
diff --git a/CR.Exceptions/Mapping/ExceptionFactoryBuilder.cs b/CR.Exceptions/Mapping/ExceptionFactoryBuilder.cs
index a85e9e2..58d2b9a 100644
--- a/CR.Exceptions/Mapping/ExceptionFactoryBuilder.cs
+++ b/CR.Exceptions/Mapping/ExceptionFactoryBuilder.cs
@@ -1,4 +1,4 @@
-namespace CR.Exceptions.Mapping;
+namespace CR.Exceptions;
 
 public class ExceptionFactoryBuilder : MapBuilder<string, Func<CrException>>
 {
diff --git a/CR.Exceptions/Mapping/ExceptionTranslator.cs b/CR.Exceptions/Mapping/ExceptionTranslator.cs
index 62d399d..23ebb75 100644
--- a/CR.Exceptions/Mapping/ExceptionTranslator.cs
+++ b/CR.Exceptions/Mapping/ExceptionTranslator.cs
@@ -1,16 +1,22 @@
-using CR.Exceptions.Extensions;
-using System.Collections.Frozen;
+using System.Collections.Frozen;
 using System.Diagnostics.CodeAnalysis;
 
-namespace CR.Exceptions.Mapping;
+namespace CR.Exceptions;
 
-public class ExceptionTranslator : TypeMap<Func<CrException>>
+public class ExceptionTranslator : TypeMap<Func<Exception, CrException>>
 {
-    internal ExceptionTranslator(FrozenDictionary<Type, Func<CrException>> dictionary) : base(dictionary) { }
+    internal ExceptionTranslator(FrozenDictionary<Type, Func<Exception, CrException>> dictionary) : base(dictionary) { }
 
-    public CrException Translate(CrException exception)
-        => GetByHierarchy(exception.GetType()).ToResult();
+    public CrException Translate(Exception exception)
+        => ExecuteTranslator(exception, GetByHierarchy(exception.GetType()));
 
-    public bool TryTranslate(CrException exception, [MaybeNullWhen(false)] out CrException translated)
-        => (translated = TryGetByHierarchy(exception.GetType(), out var translator) ? translator.ToResult() : null) != null;
+    public bool TryTranslate(Exception exception, [MaybeNullWhen(false)] out CrException translated)
+        => (translated = TryGetByHierarchy(exception.GetType(), out var translator) ? ExecuteTranslator(exception, translator) : null) != null;
+
+    private static CrException ExecuteTranslator(Exception innerException, Func<Exception, CrException> translator)
+    {
+        return
+            translator(innerException) ??
+            throw new InvalidOperationException($"{nameof(translator)} '{translator.Method.Name}' returned null.");
+    }
 }
\ No newline at end of file
diff --git a/CR.Exceptions/Mapping/ExceptionTranslatorBuilder.cs b/CR.Exceptions/Mapping/ExceptionTranslatorBuilder.cs
index 8e227f3..bcba23d 100644
--- a/CR.Exceptions/Mapping/ExceptionTranslatorBuilder.cs
+++ b/CR.Exceptions/Mapping/ExceptionTranslatorBuilder.cs
@@ -1,8 +1,8 @@
-namespace CR.Exceptions.Mapping;
+namespace CR.Exceptions;
 
-public class ExceptionTranslatorBuilder : MapBuilder<Type, Func<CrException>>
+public class ExceptionTranslatorBuilder : MapBuilder<Type, Func<Exception, CrException>>
 {
-    public ExceptionTranslatorBuilder Map<TException>(Func<CrException> translator) where TException : CrException
+    public ExceptionTranslatorBuilder Map<TException>(Func<Exception, CrException> translator) where TException : Exception
     {
         AddPair(typeof(TException), translator);
         return this;
diff --git a/CR.Exceptions/Mapping/Map.cs b/CR.Exceptions/Mapping/Map.cs
index 769c35a..e90b67a 100644
--- a/CR.Exceptions/Mapping/Map.cs
+++ b/CR.Exceptions/Mapping/Map.cs
@@ -1,7 +1,7 @@
 using System.Collections.Frozen;
 using System.Diagnostics.CodeAnalysis;
 
-namespace CR.Exceptions.Mapping;
+namespace CR.Exceptions;
 
 public abstract class Map<TKey, TValue> where TKey : notnull
 {
@@ -20,6 +20,6 @@ protected TValue GetValue(TKey key)
     protected bool TryGetValue(TKey key, [MaybeNullWhen(false)] out TValue value)
         => _dictionary.TryGetValue(key, out value);
 
-    protected KeyNotFoundException CreateKeyNotFoundException(TKey key)
+    protected KeyNotFoundException CreateKeyNotFoundException(TKey? key)
         => new($"Key '{key?.ToString() ?? "null"}' in map is not found.");
 }
\ No newline at end of file
diff --git a/CR.Exceptions/Mapping/MapBuilder.cs b/CR.Exceptions/Mapping/MapBuilder.cs
index b1f9558..73d0819 100644
--- a/CR.Exceptions/Mapping/MapBuilder.cs
+++ b/CR.Exceptions/Mapping/MapBuilder.cs
@@ -1,6 +1,6 @@
 using System.Collections.Frozen;
 
-namespace CR.Exceptions.Mapping;
+namespace CR.Exceptions;
 
 public abstract class MapBuilder<TKey, TValue> where TKey : notnull
 {
diff --git a/CR.Exceptions/Mapping/TypeMap.cs b/CR.Exceptions/Mapping/TypeMap.cs
index b671b46..7d5dc2d 100644
--- a/CR.Exceptions/Mapping/TypeMap.cs
+++ b/CR.Exceptions/Mapping/TypeMap.cs
@@ -1,7 +1,7 @@
 using System.Collections.Frozen;
 using System.Diagnostics.CodeAnalysis;
 
-namespace CR.Exceptions.Mapping;
+namespace CR.Exceptions;
 
 public abstract class TypeMap<TValue> : Map<Type, TValue>
 {
diff --git a/CR.Exceptions/README.md b/CR.Exceptions/README.md
index 815bfa0..7c12da4 100644
--- a/CR.Exceptions/README.md
+++ b/CR.Exceptions/README.md
@@ -61,13 +61,8 @@ Example:
 ```csharp
 public sealed class UserNotFoundException : NotFoundException
 {
-    public UserNotFoundException()
-        : base(
-        [
-            new CrError(
-                "IdentityUserNotFound",
-                "User was not found.")
-        ])
+    public UserNotFoundException() 
+        : base([new CrError("IdentityUserNotFound","User was not found.")])
     {
     }
 }
@@ -124,14 +119,14 @@ Registration:
 ```csharp
 ExceptionTranslator translator = new ExceptionTranslatorBuilder()
     .Map<KeycloakUserNotFoundException>(
-        static () => new UserNotFoundException())
+        static innerException => new UserNotFoundException(innerException))
     .Build();
 ```
 
 Usage:
 
 ```csharp
-catch (KeycloakUserNotFoundException ex)
+catch (Exception ex)
 {
     throw translator.Translate(ex);
 }
diff --git a/Directory.Build.props b/Directory.Build.props
index c795950..be79613 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -1,4 +1,5 @@
 <Project>
+
   <PropertyGroup>
     <Company>apptade</Company>
     <Authors>apptade</Authors>
@@ -12,4 +13,11 @@
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <NuGetPackagePrefix>CrCore</NuGetPackagePrefix>
   </PropertyGroup>
+
+  <PropertyGroup>
+    <AnalysisLevel>latest</AnalysisLevel>
+    <AnalysisMode>Recommended</AnalysisMode>
+    <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
+  </PropertyGroup>
+
 </Project>
\ No newline at end of file