diff --git a/adapter.go b/adapter.go
index 6d656a5..c0f088d 100644
--- a/adapter.go
+++ b/adapter.go
@@ -223,7 +223,7 @@ func (a *adapter) dropTable() error {
 	return nil
 }
 
-func loadPolicyLine(line CasbinRule, model model.Model) {
+func loadPolicyLine(line CasbinRule, model model.Model) error {
 	var p = []string{line.PType,
 		line.V0, line.V1, line.V2, line.V3, line.V4, line.V5}
 	var lineText string
@@ -241,7 +241,7 @@ func loadPolicyLine(line CasbinRule, model model.Model) {
 		lineText = strings.Join(p[:2], ", ")
 	}
 
-	persist.LoadPolicyLine(lineText, model)
+	return persist.LoadPolicyLine(lineText, model)
 }
 
 // LoadPolicy loads policy from database.
@@ -273,7 +273,10 @@ func (a *adapter) LoadFilteredPolicy(model model.Model, filter interface{}) erro
 		if err != nil {
 			return err
 		}
-		loadPolicyLine(line, model)
+		err = loadPolicyLine(line, model)
+		if err != nil {
+			return err
+		}
 	}
 
 	return cursor.Close(ctx)
diff --git a/adapter_test.go b/adapter_test.go
index e8cd6af..ba60194 100644
--- a/adapter_test.go
+++ b/adapter_test.go
@@ -310,7 +310,7 @@ func TestAddPolicies(t *testing.T) {
 }
 
 func TestDeleteFilteredAdapter(t *testing.T) {
-	a, err := NewFilteredAdapter(getDbURL())
+	a, err := NewFilteredAdapter(getDbURL() + "/casbin_test_new")
 	if err != nil {
 		panic(err)
 	}
@@ -329,10 +329,6 @@ func TestDeleteFilteredAdapter(t *testing.T) {
 	}
 	// The policy has a new rule: {"alice", "data1", "write"}.
 	testGetPolicy(t, e, [][]string{
-		{"alice", "data1", "read"},
-		{"bob", "data2", "write"},
-		{"data2_admin", "data2", "read"},
-		{"data2_admin", "data2", "write"},
 		{"domain1", "alice", "data3", "read", "accept", "service1"},
 		{"domain1", "alice", "data3", "write", "accept", "service2"},
 	},
@@ -343,10 +339,6 @@ func TestDeleteFilteredAdapter(t *testing.T) {
 		t.Errorf("Expected LoadPolicy() to be successful; got %v", err)
 	}
 	testGetPolicy(t, e, [][]string{
-		{"alice", "data1", "read"},
-		{"bob", "data2", "write"},
-		{"data2_admin", "data2", "read"},
-		{"data2_admin", "data2", "write"},
 		{"domain1", "alice", "data3", "write", "accept", "service2"},
 	},
 	)
@@ -355,12 +347,7 @@ func TestDeleteFilteredAdapter(t *testing.T) {
 	if err := e.LoadPolicy(); err != nil {
 		t.Errorf("Expected LoadPolicy() to be successful; got %v", err)
 	}
-	testGetPolicy(t, e, [][]string{
-		{"alice", "data1", "read"},
-		{"bob", "data2", "write"},
-		{"data2_admin", "data2", "read"},
-		{"data2_admin", "data2", "write"},
-	},
+	testGetPolicy(t, e, [][]string{},
 	)
 }
 
diff --git a/go.mod b/go.mod
index 88bb342..143035c 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,6 @@ module github.com/casbin/mongodb-adapter/v3
 go 1.13
 
 require (
-	github.com/casbin/casbin/v2 v2.31.2
+	github.com/casbin/casbin/v2 v2.55.0
 	go.mongodb.org/mongo-driver v1.5.3
 )
diff --git a/go.sum b/go.sum
index 1892bf3..f2e7a0b 100644
--- a/go.sum
+++ b/go.sum
@@ -3,8 +3,8 @@ github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible h1
 github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=
 github.com/aws/aws-sdk-go v1.34.28 h1:sscPpn/Ns3i0F4HPEWAVcwdIRaZZCuL7llJ2/60yPIk=
 github.com/aws/aws-sdk-go v1.34.28/go.mod h1:H7NKnBqNVzoTJpGfLrQkkD+ytBA93eiDYi/+8rV9s48=
-github.com/casbin/casbin/v2 v2.31.2 h1:L2RDbKhkspfUPkY12PvJ2oN2QtBQhJ5oV6bq9QfKGHo=
-github.com/casbin/casbin/v2 v2.31.2/go.mod h1:vByNa/Fchek0KZUgG5wEsl7iFsiviAYKRtgrQfcJqHg=
+github.com/casbin/casbin/v2 v2.55.0 h1:RyU+OacnVzjxof1U3bmxHM7oCRdx9+gNnkclrvof/zI=
+github.com/casbin/casbin/v2 v2.55.0/go.mod h1:vByNa/Fchek0KZUgG5wEsl7iFsiviAYKRtgrQfcJqHg=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=