<?xml version="1.0" encoding=ISO-8859-1" ?>
<!-- Error: " char missing. Correct: encoding="ISO-8859-1" -->
<abc:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<!-- Error: unbound prefix. Correct: <xsd:schema -->

<xsd:simpleType name="EmailType">
    <xsd:restriction base="xsd:string">
        <xsd:pattern value="[a-z.]*@[a-z]*.[a-z]*">
        <!-- Error: unterminated element. Correct: [a-z]*"/> -->
    </xsd:restriction>
</xsd:simpleType>

<xsd:complexType name="FriendType">
    <xsd:sequence>
        <xsd:elephant name="email" type="EmailType" minOccurs="1"/>
        <!-- Error: incorrect content. Correct: <xsd:element -->
    </xsd:sequence>
    <xsd:attribute name="nickname" use="required" type="xsd:string"/>
    <xsd:attribute name="birthday" type="xsd:data"/>
    <!-- Error: unknown type. Correct: "xsd:date" -->
</xsd:complexType>

<xsd:element name="address book">
<!-- Error: invalid attribute value. Correct: ="addressbook" -->
    <xsd:complexType>
        <xsd:sequence>
            <xsd:element name="friend" type="FriendType" maxOccur="unbounded"/>
            <!-- Error: invalid attribute. Correct: maxOccurs=" -->
        </xsd:sequence>
    </xsd:complexType>
</xsd:element>
</xsd:schema>