为什么会报错，明明和视频中的一样

<?xml version="1.0" encoding="UTF-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema">
    <element name="hr">
        <!-- 
            complexType标签含义是复杂节点
            包含子节点时必须使用这个标签
             
            required必须存在的
             
            minOccurs="1"这个节点最少要出现一次
             
            simpleType简单类型的约束
             
            restriction限定
             
            base="integer"进行整数方面的限制
             
            minInclusive 允许出现的最小整数是多少
         -->
        <complexType>
            <sequence>
                <element name="employee" minOccurs="1" maxOccurs="9999">
                    <complexType>
                        <sequence>
                            <element name="name" type="string"></element>
                            <element name="age">
                                <simpleType>
                                    <restriction base="integer">
                                        <minInclusive value="18"></minInclusive>
                                        <maxInclusive value="60"></maxInclusive>
                                    </restriction>
                                </simpleType>
                            </element>
                            <element name="salary" type="integer"></element>
                            <element name="department">
                                <complexType>
                                    <sequence>
                                        <element name="dname" type="string"></element>
                                        <element name="address" type="string"></element>
                                    </sequence>
                                </complexType>
                            </element>
                        </sequence>
                        <attribute name="no" type="string" use="required"></attribute>
                    </complexType>
                </element>
            </sequence>
        </complexType>     
    </element>
</schema>