diff --git a/NetCasbin.UnitTest/EnforcerTest.cs b/NetCasbin.UnitTest/EnforcerTest.cs
index 37ea2ccb..7ff76884 100644
--- a/NetCasbin.UnitTest/EnforcerTest.cs
+++ b/NetCasbin.UnitTest/EnforcerTest.cs
@@ -23,6 +23,7 @@ public EnforcerTest(ITestOutputHelper testOutputHelper, TestModelFixture testMod
             _testModelFixture = testModelFixture;
         }
 
+        #region In memory model
         [Fact]
         public void TestKeyMatchModelInMemory()
         {
@@ -379,6 +380,144 @@ public async Task TestNotUsedRbacModelInMemoryAsync()
             await TestEnforceAsync(e, "bob", "data2", "write", true);
         }
 
+        [Fact]
+        public void TestMultipleGroupTypeModelInMemory()
+        {
+            var m = Model.Model.CreateDefault();
+            m.AddDef("r", "r", "sub, obj, act");
+            m.AddDef("p", "p", "sub, obj, act");
+            m.AddDef("g", "g", "_, _");
+            m.AddDef("g", "g2", "_, _");
+            m.AddDef("e", "e", "some(where (p.eft == allow))");
+            m.AddDef("m", "m", "g(r.sub, p.sub) && g2(r.obj, p.obj) && r.act == p.act");
+
+            var e = new Enforcer(m);
+            e.AddPolicy("alice", "data1", "read");
+            e.AddPolicy("bob", "data2", "write");
+            e.AddPolicy("data_group_admin", "data_group", "write");
+            e.AddNamedGroupingPolicy("g", "alice", "data_group_admin");
+            e.AddNamedGroupingPolicy("g2", "data1", "data_group");
+            e.AddNamedGroupingPolicy("g2", "data2", "data_group");
+
+            Assert.True(e.Enforce("alice", "data1", "read"));
+            Assert.True(e.Enforce("alice", "data1", "write"));
+            Assert.False(e.Enforce("alice", "data2", "read"));
+            Assert.True(e.Enforce("alice", "data2", "write"));
+        }
+
+        [Fact]
+        public async Task TestMultipleGroupTypeModelInMemoryAsync()
+        {
+            var m = Model.Model.CreateDefault();
+            m.AddDef("r", "r", "sub, obj, act");
+            m.AddDef("p", "p", "sub, obj, act");
+            m.AddDef("g", "g", "_, _");
+            m.AddDef("g", "g2", "_, _");
+            m.AddDef("e", "e", "some(where (p.eft == allow))");
+            m.AddDef("m", "m", "g(r.sub, p.sub) && g2(r.obj, p.obj) && r.act == p.act");
+
+            var e = new Enforcer(m);
+            await e.AddPolicyAsync("alice", "data1", "read");
+            await e.AddPolicyAsync("bob", "data2", "write");
+            await e.AddPolicyAsync("data_group_admin", "data_group", "write");
+            await e.AddNamedGroupingPolicyAsync("g", "alice", "data_group_admin");
+            await e.AddNamedGroupingPolicyAsync("g2", "data1", "data_group");
+            await e.AddNamedGroupingPolicyAsync("g2", "data2", "data_group");
+
+            Assert.True(await e.EnforceAsync("alice", "data1", "read"));
+            Assert.True(await e.EnforceAsync("alice", "data1", "write"));
+            Assert.False(await e.EnforceAsync("alice", "data2", "read"));
+            Assert.True(await e.EnforceAsync("alice", "data2", "write"));
+        }
+        #endregion
+
+        #region Init enmpty
+        [Fact]
+        public void TestInitEmpty()
+        {
+            var e = new Enforcer();
+
+            var m = Model.Model.CreateDefault();
+            m.AddDef("r", "r", "sub, obj, act");
+            m.AddDef("p", "p", "sub, obj, act");
+            m.AddDef("e", "e", "some(where (p.eft == allow))");
+            m.AddDef("m", "m", "r.sub == p.sub && keyMatch(r.obj, p.obj) && regexMatch(r.act, p.act)");
+
+            IAdapter a = new DefaultFileAdapter("examples/keymatch_policy.csv");
+
+            e.SetModel(m);
+            e.SetAdapter(a);
+            e.LoadPolicy();
+
+            TestEnforce(e, "alice", "/alice_data/resource1", "GET", true);
+        }
+
+        [Fact]
+        public async Task TestInitEmptyAsync()
+        {
+            var e = new Enforcer();
+
+            var m = Model.Model.CreateDefault();
+            m.AddDef("r", "r", "sub, obj, act");
+            m.AddDef("p", "p", "sub, obj, act");
+            m.AddDef("e", "e", "some(where (p.eft == allow))");
+            m.AddDef("m", "m", "r.sub == p.sub && keyMatch(r.obj, p.obj) && regexMatch(r.act, p.act)");
+
+            IAdapter a = new DefaultFileAdapter("examples/keymatch_policy.csv");
+
+            e.SetModel(m);
+            e.SetAdapter(a);
+            await e.LoadPolicyAsync();
+
+            await TestEnforceAsync(e, "alice", "/alice_data/resource1", "GET", true);
+        }
+
+        [Fact]
+        public void TestInitEmptyByInputStream()
+        {
+            var e = new Enforcer();
+
+            var m = Model.Model.CreateDefault();
+            m.AddDef("r", "r", "sub, obj, act");
+            m.AddDef("p", "p", "sub, obj, act");
+            m.AddDef("e", "e", "some(where (p.eft == allow))");
+            m.AddDef("m", "m", "r.sub == p.sub && keyMatch(r.obj, p.obj) && regexMatch(r.act, p.act)");
+
+            using (var fs = new FileStream("examples/keymatch_policy.csv", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
+            {
+                IAdapter a = new DefaultFileAdapter(fs);
+                e.SetModel(m);
+                e.SetAdapter(a);
+                e.LoadPolicy();
+
+                TestEnforce(e, "alice", "/alice_data/resource1", "GET", true);
+            }
+        }
+
+        [Fact]
+        public async Task TestInitEmptyByInputStreamAsync()
+        {
+            var e = new Enforcer();
+
+            var m = Model.Model.CreateDefault();
+            m.AddDef("r", "r", "sub, obj, act");
+            m.AddDef("p", "p", "sub, obj, act");
+            m.AddDef("e", "e", "some(where (p.eft == allow))");
+            m.AddDef("m", "m", "r.sub == p.sub && keyMatch(r.obj, p.obj) && regexMatch(r.act, p.act)");
+
+            using (var fs = new FileStream("examples/keymatch_policy.csv", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
+            {
+                IAdapter a = new DefaultFileAdapter(fs);
+                e.SetModel(m);
+                e.SetAdapter(a);
+                await e.LoadPolicyAsync();
+
+                await TestEnforceAsync(e, "alice", "/alice_data/resource1", "GET", true);
+            }
+        }
+        #endregion
+
+        #region Policy management
         [Fact]
         public void TestReloadPolicy()
         {
@@ -436,7 +575,9 @@ public void TestClearPolicy()
 
             e.ClearPolicy();
         }
+        #endregion
 
+        #region Extension features
         [Fact]
         public void TestEnableEnforce()
         {
@@ -671,90 +812,9 @@ public async Task TestSetAdapterFromFileAsync()
             await TestEnforceAsync(e, "alice", "data1", "read", true);
         }
 
-        [Fact]
-        public void TestInitEmpty()
-        {
-            var e = new Enforcer();
-
-            var m = Model.Model.CreateDefault();
-            m.AddDef("r", "r", "sub, obj, act");
-            m.AddDef("p", "p", "sub, obj, act");
-            m.AddDef("e", "e", "some(where (p.eft == allow))");
-            m.AddDef("m", "m", "r.sub == p.sub && keyMatch(r.obj, p.obj) && regexMatch(r.act, p.act)");
-
-            IAdapter a = new DefaultFileAdapter("examples/keymatch_policy.csv");
-
-            e.SetModel(m);
-            e.SetAdapter(a);
-            e.LoadPolicy();
-
-            TestEnforce(e, "alice", "/alice_data/resource1", "GET", true);
-        }
-
-        [Fact]
-        public async Task TestInitEmptyAsync()
-        {
-            var e = new Enforcer();
-
-            var m = Model.Model.CreateDefault();
-            m.AddDef("r", "r", "sub, obj, act");
-            m.AddDef("p", "p", "sub, obj, act");
-            m.AddDef("e", "e", "some(where (p.eft == allow))");
-            m.AddDef("m", "m", "r.sub == p.sub && keyMatch(r.obj, p.obj) && regexMatch(r.act, p.act)");
-
-            IAdapter a = new DefaultFileAdapter("examples/keymatch_policy.csv");
-
-            e.SetModel(m);
-            e.SetAdapter(a);
-            await e.LoadPolicyAsync();
-
-            await TestEnforceAsync(e, "alice", "/alice_data/resource1", "GET", true);
-        }
-
-        [Fact]
-        public void TestInitEmptyByInputStream()
-        {
-            var e = new Enforcer();
-
-            var m = Model.Model.CreateDefault();
-            m.AddDef("r", "r", "sub, obj, act");
-            m.AddDef("p", "p", "sub, obj, act");
-            m.AddDef("e", "e", "some(where (p.eft == allow))");
-            m.AddDef("m", "m", "r.sub == p.sub && keyMatch(r.obj, p.obj) && regexMatch(r.act, p.act)");
-
-            using (var fs = new FileStream("examples/keymatch_policy.csv", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
-            {
-                IAdapter a = new DefaultFileAdapter(fs);
-                e.SetModel(m);
-                e.SetAdapter(a);
-                e.LoadPolicy();
-
-                TestEnforce(e, "alice", "/alice_data/resource1", "GET", true);
-            }
-        }
-
-        [Fact]
-        public async Task TestInitEmptyByInputStreamAsync()
-        {
-            var e = new Enforcer();
-
-            var m = Model.Model.CreateDefault();
-            m.AddDef("r", "r", "sub, obj, act");
-            m.AddDef("p", "p", "sub, obj, act");
-            m.AddDef("e", "e", "some(where (p.eft == allow))");
-            m.AddDef("m", "m", "r.sub == p.sub && keyMatch(r.obj, p.obj) && regexMatch(r.act, p.act)");
-
-            using (var fs = new FileStream("examples/keymatch_policy.csv", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
-            {
-                IAdapter a = new DefaultFileAdapter(fs);
-                e.SetModel(m);
-                e.SetAdapter(a);
-                await e.LoadPolicyAsync();
-
-                await TestEnforceAsync(e, "alice", "/alice_data/resource1", "GET", true);
-            }
-        }
+        #endregion
 
+        #region EnforceEx API
         [Fact]
         public void TestEnforceExApi()
         {
@@ -854,5 +914,6 @@ public void TestEnforceExApiLog()
             e.Logger = null;
         }
 #endif
+        #endregion
     }
 }
diff --git a/NetCasbin/ManagementEnforcer.cs b/NetCasbin/ManagementEnforcer.cs
index cc95e0a6..631c816f 100644
--- a/NetCasbin/ManagementEnforcer.cs
+++ b/NetCasbin/ManagementEnforcer.cs
@@ -740,6 +740,19 @@ public bool AddNamedGroupingPolicy(string ptype, params string[] parameters)
             return AddNamedGroupingPolicy(ptype, parameters.ToList());
         }
 
+        /// <summary>
+        /// Adds a named role inheritance rule to the current 
+        /// policy. If the rule already exists, the function returns false and the rule
+        /// will not be added. Otherwise the function returns true by adding the new rule.
+        /// </summary>
+        /// <param name="ptype">The policy type, can be "g", "g2", "g3", ..</param>
+        /// <param name="parameters">The "g" policy rule.</param>
+        /// <returns>Succeeds or not.</returns>
+        public Task<bool> AddNamedGroupingPolicyAsync(string ptype, params string[] parameters)
+        {
+            return AddNamedGroupingPolicyAsync(ptype, parameters.ToList());
+        }
+
         /// <summary>
         /// Adds roles inheritance rule to the current policy. If the
         /// rule already exists, the function returns false and the rule will not be
diff --git a/NetCasbin/Model/Model.cs b/NetCasbin/Model/Model.cs
index ac2f36c5..a45db7bd 100644
--- a/NetCasbin/Model/Model.cs
+++ b/NetCasbin/Model/Model.cs
@@ -74,6 +74,13 @@ public void LoadModelFromText(string text)
             LoadModel(Config.Config.NewConfigFromText(text));
         }
 
+        /// <summary>
+        /// Adds an assertion to the model.
+        /// </summary>
+        /// <param name="section"></param>
+        /// <param name="key">Key of the assertion, it is same to "policyType" when section is "p" or "g".</param>
+        /// <param name="value">Value of the assertion.</param>
+        /// <returns></returns>
         public bool AddDef(string section, string key, string value)
         {
             if (string.IsNullOrWhiteSpace(value))
@@ -90,7 +97,7 @@ public bool AddDef(string section, string key, string value)
             if (section.Equals(PermConstants.Section.RequestSection) ||
                 section.Equals(PermConstants.Section.PolicySection))
             {
-                var tokens = assertion.Value
+                string[] tokens = assertion.Value
                     .Split(PermConstants.PolicySeparatorChar)
                     .Select(t => t.Trim()).ToArray();
 
@@ -108,7 +115,7 @@ public bool AddDef(string section, string key, string value)
                 assertion.Value = Utility.RemoveComments(Utility.EscapeAssertion(assertion.Value));
             }
 
-            if (!Model.ContainsKey(section))
+            if (Model.ContainsKey(section) is false)
             {
                 var assertionMap = new Dictionary<string, Assertion>
                 {