diff --git a/container/gtree/gtree_btree.go b/container/gtree/gtree_btree.go
index 770dec588..fcd49075f 100644
--- a/container/gtree/gtree_btree.go
+++ b/container/gtree/gtree_btree.go
@@ -346,7 +346,10 @@ func (tree *BTree) Left() *BTreeEntry {
 	tree.mu.RLock()
 	defer tree.mu.RUnlock()
 	node := tree.left(tree.root)
-	return node.Entries[0]
+	if node != nil {
+		return node.Entries[0]
+	}
+	return nil
 }
 
 // Right returns the right-most (max) entry or nil if tree is empty.
@@ -354,7 +357,10 @@ func (tree *BTree) Right() *BTreeEntry {
 	tree.mu.RLock()
 	defer tree.mu.RUnlock()
 	node := tree.right(tree.root)
-	return node.Entries[len(node.Entries)-1]
+	if node != nil {
+		return node.Entries[len(node.Entries)-1]
+	}
+	return nil
 }
 
 // String returns a string representation of container (for debugging purposes)
@@ -931,7 +937,7 @@ func (tree *BTree) deleteChild(node *BTreeNode, index int) {
 
 // MarshalJSON implements the interface MarshalJSON for json.Marshal.
 func (tree *BTree) MarshalJSON() ([]byte, error) {
-	return json.Marshal(tree.Map())
+	return json.Marshal(tree.MapStrAny())
 }
 
 // getComparator returns the comparator if it's previously set,
diff --git a/container/gtree/gtree_z_example_avltree_test.go b/container/gtree/gtree_z_example_avltree_test.go
new file mode 100644
index 000000000..f96f52a07
--- /dev/null
+++ b/container/gtree/gtree_z_example_avltree_test.go
@@ -0,0 +1,7 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with gm file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package gtree_test
diff --git a/container/gtree/gtree_z_example_btree_test.go b/container/gtree/gtree_z_example_btree_test.go
new file mode 100644
index 000000000..9bd3df40a
--- /dev/null
+++ b/container/gtree/gtree_z_example_btree_test.go
@@ -0,0 +1,672 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with gm file,
+// You can obtain one at https://github.com/Agogf/gf.
+
+package gtree_test
+
+import (
+	"fmt"
+	"github.com/gogf/gf/v2/container/gtree"
+	"github.com/gogf/gf/v2/internal/json"
+	"github.com/gogf/gf/v2/util/gconv"
+	"github.com/gogf/gf/v2/util/gutil"
+)
+
+func ExampleBTree_Clone() {
+	b := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		b.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	tree := b.Clone()
+
+	fmt.Println(tree.Map())
+	fmt.Println(tree.Size())
+
+	// Output:
+	// map[key0:val0 key1:val1 key2:val2 key3:val3 key4:val4 key5:val5]
+	// 6
+}
+
+func ExampleBTree_Set() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Map())
+	fmt.Println(tree.Size())
+
+	// Output:
+	// map[key0:val0 key1:val1 key2:val2 key3:val3 key4:val4 key5:val5]
+	// 6
+}
+
+func ExampleBTree_Sets() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+
+	tree.Sets(map[interface{}]interface{}{
+		"key1": "val1",
+		"key2": "val2",
+	})
+
+	fmt.Println(tree.Map())
+	fmt.Println(tree.Size())
+
+	// Output:
+	// map[key1:val1 key2:val2]
+	// 2
+}
+
+func ExampleBTree_Get() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Get("key1"))
+	fmt.Println(tree.Get("key10"))
+
+	// Output:
+	// val1
+	// <nil>
+}
+
+func ExampleBTree_GetOrSet() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.GetOrSet("key1", "newVal1"))
+	fmt.Println(tree.GetOrSet("key6", "val6"))
+
+	// Output:
+	// val1
+	// val6
+}
+
+func ExampleBTree_GetOrSetFunc() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.GetOrSetFunc("key1", func() interface{} {
+		return "newVal1"
+	}))
+	fmt.Println(tree.GetOrSetFunc("key6", func() interface{} {
+		return "val6"
+	}))
+
+	// Output:
+	// val1
+	// val6
+}
+
+func ExampleBTree_GetOrSetFuncLock() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.GetOrSetFuncLock("key1", func() interface{} {
+		return "newVal1"
+	}))
+	fmt.Println(tree.GetOrSetFuncLock("key6", func() interface{} {
+		return "val6"
+	}))
+
+	// Output:
+	// val1
+	// val6
+}
+
+func ExampleBTree_GetVar() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.GetVar("key1").String())
+
+	// Output:
+	// val1
+}
+
+func ExampleBTree_GetVarOrSet() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.GetVarOrSet("key1", "newVal1"))
+	fmt.Println(tree.GetVarOrSet("key6", "val6"))
+
+	// Output:
+	// val1
+	// val6
+}
+
+func ExampleBTree_GetVarOrSetFunc() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.GetVarOrSetFunc("key1", func() interface{} {
+		return "newVal1"
+	}))
+	fmt.Println(tree.GetVarOrSetFunc("key6", func() interface{} {
+		return "val6"
+	}))
+
+	// Output:
+	// val1
+	// val6
+}
+
+func ExampleBTree_GetVarOrSetFuncLock() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.GetVarOrSetFuncLock("key1", func() interface{} {
+		return "newVal1"
+	}))
+	fmt.Println(tree.GetVarOrSetFuncLock("key6", func() interface{} {
+		return "val6"
+	}))
+
+	// Output:
+	// val1
+	// val6
+}
+
+func ExampleBTree_SetIfNotExist() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.SetIfNotExist("key1", "newVal1"))
+	fmt.Println(tree.SetIfNotExist("key6", "val6"))
+
+	// Output:
+	// false
+	// true
+}
+
+func ExampleBTree_SetIfNotExistFunc() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.SetIfNotExistFunc("key1", func() interface{} {
+		return "newVal1"
+	}))
+	fmt.Println(tree.SetIfNotExistFunc("key6", func() interface{} {
+		return "val6"
+	}))
+
+	// Output:
+	// false
+	// true
+}
+
+func ExampleBTree_SetIfNotExistFuncLock() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.SetIfNotExistFuncLock("key1", func() interface{} {
+		return "newVal1"
+	}))
+	fmt.Println(tree.SetIfNotExistFuncLock("key6", func() interface{} {
+		return "val6"
+	}))
+
+	// Output:
+	// false
+	// true
+}
+
+func ExampleBTree_Contains() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Contains("key1"))
+	fmt.Println(tree.Contains("key6"))
+
+	// Output:
+	// true
+	// false
+}
+
+func ExampleBTree_Remove() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Remove("key1"))
+	fmt.Println(tree.Remove("key6"))
+	fmt.Println(tree.Map())
+
+	// Output:
+	// val1
+	// <nil>
+	// map[key0:val0 key2:val2 key3:val3 key4:val4 key5:val5]
+}
+
+func ExampleBTree_Removes() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	removeKeys := make([]interface{}, 2)
+	removeKeys = append(removeKeys, "key1")
+	removeKeys = append(removeKeys, "key6")
+
+	tree.Removes(removeKeys)
+
+	fmt.Println(tree.Map())
+
+	// Output:
+	// map[key0:val0 key2:val2 key3:val3 key4:val4 key5:val5]
+}
+
+func ExampleBTree_IsEmpty() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+
+	fmt.Println(tree.IsEmpty())
+
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.IsEmpty())
+
+	// Output:
+	// true
+	// false
+}
+
+func ExampleBTree_Size() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+
+	fmt.Println(tree.Size())
+
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Size())
+
+	// Output:
+	// 0
+	// 6
+}
+
+func ExampleBTree_Keys() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 6; i > 0; i-- {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Keys())
+
+	// Output:
+	// [key1 key2 key3 key4 key5 key6]
+}
+
+func ExampleBTree_Values() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 6; i > 0; i-- {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Values())
+
+	// Output:
+	// [val1 val2 val3 val4 val5 val6]
+}
+
+func ExampleBTree_Map() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Map())
+
+	// Output:
+	// map[key0:val0 key1:val1 key2:val2 key3:val3 key4:val4 key5:val5]
+}
+
+func ExampleBTree_MapStrAny() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set(1000+i, "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.MapStrAny())
+
+	// Output:
+	// map[1000:val0 1001:val1 1002:val2 1003:val3 1004:val4 1005:val5]
+}
+
+func ExampleBTree_Clear() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set(1000+i, "val"+gconv.String(i))
+	}
+	fmt.Println(tree.Size())
+
+	tree.Clear()
+	fmt.Println(tree.Size())
+
+	// Output:
+	// 6
+	// 0
+}
+
+func ExampleBTree_Replace() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Map())
+
+	data := map[interface{}]interface{}{
+		"newKey0": "newVal0",
+		"newKey1": "newVal1",
+		"newKey2": "newVal2",
+	}
+
+	tree.Replace(data)
+
+	fmt.Println(tree.Map())
+
+	// Output:
+	// map[key0:val0 key1:val1 key2:val2 key3:val3 key4:val4 key5:val5]
+	// map[newKey0:newVal0 newKey1:newVal1 newKey2:newVal2]
+}
+
+func ExampleBTree_Height() {
+	tree := gtree.NewBTree(3, gutil.ComparatorInt)
+	for i := 0; i < 100; i++ {
+		tree.Set(i, i)
+	}
+	fmt.Println(tree.Height())
+
+	// Output:
+	// 6
+}
+
+func ExampleBTree_Left() {
+	tree := gtree.NewBTree(3, gutil.ComparatorInt)
+	for i := 1; i < 100; i++ {
+		tree.Set(i, i)
+	}
+	fmt.Println(tree.Left().Key, tree.Left().Value)
+
+	emptyTree := gtree.NewBTree(3, gutil.ComparatorInt)
+	fmt.Println(emptyTree.Left())
+
+	// Output:
+	// 1 1
+	// <nil>
+}
+
+func ExampleBTree_Right() {
+	tree := gtree.NewBTree(3, gutil.ComparatorInt)
+	for i := 1; i < 100; i++ {
+		tree.Set(i, i)
+	}
+	fmt.Println(tree.Right().Key, tree.Right().Value)
+
+	emptyTree := gtree.NewBTree(3, gutil.ComparatorInt)
+	fmt.Println(emptyTree.Left())
+
+	// Output:
+	// 99 99
+	// <nil>
+}
+
+func ExampleBTree_String() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.String())
+
+	// Output:
+	// key0
+	// key1
+	//     key2
+	// key3
+	//     key4
+	//     key5
+}
+
+func ExampleBTree_Search() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	fmt.Println(tree.Search("key0"))
+	fmt.Println(tree.Search("key6"))
+
+	// Output:
+	// val0 true
+	// <nil> false
+}
+
+func ExampleBTree_Print() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	tree.Print()
+
+	// Output:
+	// key0
+	// key1
+	//     key2
+	// key3
+	//     key4
+	//     key5
+}
+
+func ExampleBTree_Iterator() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 10; i++ {
+		tree.Set(i, 10-i)
+	}
+
+	var totalKey, totalValue int
+	tree.Iterator(func(key, value interface{}) bool {
+		totalKey += key.(int)
+		totalValue += value.(int)
+
+		return totalValue < 20
+	})
+
+	fmt.Println("totalKey:", totalKey)
+	fmt.Println("totalValue:", totalValue)
+
+	// Output:
+	// totalKey: 3
+	// totalValue: 27
+}
+
+func ExampleBTree_IteratorFrom() {
+	m := make(map[interface{}]interface{})
+	for i := 1; i <= 5; i++ {
+		m[i] = i * 10
+	}
+	tree := gtree.NewBTreeFrom(3, gutil.ComparatorInt, m)
+
+	tree.IteratorFrom(1, true, func(key, value interface{}) bool {
+		fmt.Println("key:", key, ", value:", value)
+		return true
+	})
+
+	// Output:
+	// key: 1 , value: 10
+	// key: 2 , value: 20
+	// key: 3 , value: 30
+	// key: 4 , value: 40
+	// key: 5 , value: 50
+}
+
+func ExampleBTree_IteratorAsc() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 10; i++ {
+		tree.Set(i, 10-i)
+	}
+
+	tree.IteratorAsc(func(key, value interface{}) bool {
+		fmt.Println("key:", key, ", value:", value)
+		return true
+	})
+
+	// Output:
+	// key: 0 , value: 10
+	// key: 1 , value: 9
+	// key: 2 , value: 8
+	// key: 3 , value: 7
+	// key: 4 , value: 6
+	// key: 5 , value: 5
+	// key: 6 , value: 4
+	// key: 7 , value: 3
+	// key: 8 , value: 2
+	// key: 9 , value: 1
+}
+
+func ExampleBTree_IteratorAscFrom_Normal() {
+	m := make(map[interface{}]interface{})
+	for i := 1; i <= 5; i++ {
+		m[i] = i * 10
+	}
+	tree := gtree.NewBTreeFrom(3, gutil.ComparatorInt, m)
+
+	tree.IteratorAscFrom(1, true, func(key, value interface{}) bool {
+		fmt.Println("key:", key, ", value:", value)
+		return true
+	})
+
+	// Output:
+	// key: 1 , value: 10
+	// key: 2 , value: 20
+	// key: 3 , value: 30
+	// key: 4 , value: 40
+	// key: 5 , value: 50
+}
+
+func ExampleBTree_IteratorAscFrom_NoExistKey() {
+	m := make(map[interface{}]interface{})
+	for i := 1; i <= 5; i++ {
+		m[i] = i * 10
+	}
+	tree := gtree.NewBTreeFrom(3, gutil.ComparatorInt, m)
+
+	tree.IteratorAscFrom(0, true, func(key, value interface{}) bool {
+		fmt.Println("key:", key, ", value:", value)
+		return true
+	})
+
+	// Output:
+}
+
+func ExampleBTree_IteratorAscFrom_NoExistKeyAndMatchFalse() {
+	m := make(map[interface{}]interface{})
+	for i := 1; i <= 5; i++ {
+		m[i] = i * 10
+	}
+	tree := gtree.NewBTreeFrom(3, gutil.ComparatorInt, m)
+
+	tree.IteratorAscFrom(0, false, func(key, value interface{}) bool {
+		fmt.Println("key:", key, ", value:", value)
+		return true
+	})
+
+	// Output:
+	// key: 1 , value: 10
+	// key: 2 , value: 20
+	// key: 3 , value: 30
+	// key: 4 , value: 40
+	// key: 5 , value: 50
+}
+
+func ExampleBTree_IteratorDesc() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 10; i++ {
+		tree.Set(i, 10-i)
+	}
+
+	tree.IteratorDesc(func(key, value interface{}) bool {
+		fmt.Println("key:", key, ", value:", value)
+		return true
+	})
+
+	// Output:
+	// key: 9 , value: 1
+	// key: 8 , value: 2
+	// key: 7 , value: 3
+	// key: 6 , value: 4
+	// key: 5 , value: 5
+	// key: 4 , value: 6
+	// key: 3 , value: 7
+	// key: 2 , value: 8
+	// key: 1 , value: 9
+	// key: 0 , value: 10
+}
+
+func ExampleBTree_IteratorDescFrom() {
+	m := make(map[interface{}]interface{})
+	for i := 1; i <= 5; i++ {
+		m[i] = i * 10
+	}
+	tree := gtree.NewBTreeFrom(3, gutil.ComparatorInt, m)
+
+	tree.IteratorDescFrom(5, true, func(key, value interface{}) bool {
+		fmt.Println("key:", key, ", value:", value)
+		return true
+	})
+
+	// Output:
+	// key: 5 , value: 50
+	// key: 4 , value: 40
+	// key: 3 , value: 30
+	// key: 2 , value: 20
+	// key: 1 , value: 10
+}
+
+func ExampleBTree_MarshalJSON() {
+	tree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		tree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	bytes, err := json.Marshal(tree)
+	if err == nil {
+		fmt.Println(gconv.String(bytes))
+	}
+
+	// Output:
+	// {"key0":"val0","key1":"val1","key2":"val2","key3":"val3","key4":"val4","key5":"val5"}
+}
diff --git a/container/gtree/gtree_z_example_redblacktree_test.go b/container/gtree/gtree_z_example_redblacktree_test.go
new file mode 100644
index 000000000..f96f52a07
--- /dev/null
+++ b/container/gtree/gtree_z_example_redblacktree_test.go
@@ -0,0 +1,7 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with gm file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package gtree_test
diff --git a/container/gtree/gtree_z_example_test.go b/container/gtree/gtree_z_example_test.go
new file mode 100644
index 000000000..a6153a324
--- /dev/null
+++ b/container/gtree/gtree_z_example_test.go
@@ -0,0 +1,54 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with gm file,
+// You can obtain one at https://github.com/Agogf/gf.
+
+package gtree_test
+
+import (
+	"fmt"
+	"github.com/gogf/gf/v2/container/gtree"
+	"github.com/gogf/gf/v2/util/gconv"
+	"github.com/gogf/gf/v2/util/gutil"
+)
+
+func ExampleNewAVLTree() {
+
+}
+
+func ExampleNewAVLTreeFrom() {
+
+}
+
+func ExampleNewBTree() {
+	bTree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		bTree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+	fmt.Println(bTree.Map())
+
+	// Output:
+	// map[key0:val0 key1:val1 key2:val2 key3:val3 key4:val4 key5:val5]
+}
+
+func ExampleNewBTreeFrom() {
+	bTree := gtree.NewBTree(3, gutil.ComparatorString)
+	for i := 0; i < 6; i++ {
+		bTree.Set("key"+gconv.String(i), "val"+gconv.String(i))
+	}
+
+	otherBTree := gtree.NewBTreeFrom(3, gutil.ComparatorString, bTree.Map())
+	fmt.Println(otherBTree.Map())
+
+	// Output:
+	// map[key0:val0 key1:val1 key2:val2 key3:val3 key4:val4 key5:val5]
+}
+
+func ExampleNewRedBlackTree() {
+
+}
+
+func ExampleNewRedBlackTreeFrom() {
+
+}