xml – XSD错误：不允许使用字符内容,因为内容类型为空

我从以下XSD收到验证错误：

<?xml version="1.0" ?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   <xsd:element name="People">
      <xsd:complexType>
         <xsd:sequence>
            <xsd:element name="Person" maxOccurs="unbounded">
                 <xsd:complexType>
                    <xsd:attribute name="name" type="xsd:string" use="required" />
                 </xsd:complexType>
             </xsd:element>
         </xsd:sequence>
      </xsd:complexType>
   </xsd:element>
</xsd:schema>

使用以下XML进行验证时：

<?xml version="1.0" ?>
<People>
    <Person name='john'>
        a nice person
    </Person>
    <Person name='sarah'>
        a very nice person
    </Person>
    <Person name='chris'>
        the nicest person in the world
   </Person>
</People>

返回以下错误：

lxml.etree.XMLSyntaxError: Element 'Person': Character content is not allowed,because the content type is empty.

我错过了什么？

它说“人”不能包含字符串.要使用xsd验证xml,请使用以下命令：

<?xml version="1.0" ?>
<People>
    <Person name='john'>
    </Person>
    <Person name='sarah'>
    </Person>
    <Person name='chris'>
   </Person>
</People>

尝试使用xsd进行验证：

<?xml version="1.0" ?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   <xsd:element name="People">
      <xsd:complexType>
         <xsd:sequence>
         <xsd:element name="Person" type="Person" maxOccurs="unbounded"/>
         </xsd:sequence>
      </xsd:complexType>
   </xsd:element>

   <xsd:complexType name="Person">
     <xsd:simpleContent>
        <xsd:extension base="xsd:string">
           <xsd:attribute name="name" type="xsd:string" use="required" />
        </xsd:extension>
    </xsd:simpleContent>
   </xsd:complexType>
</xsd:schema>