<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           elementFormDefault="qualified">

    <xs:element name="Document">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="Para" maxOccurs="unbounded">
                    <xs:complexType>
                        <xs:simpleContent>
                            <xs:extension base="paraType">
                                <xs:attribute name="classification" type="classificationLevels" use="required"/>
                            </xs:extension>
                        </xs:simpleContent>
                    </xs:complexType>
                </xs:element>
            </xs:sequence>
            <xs:attribute name="classification" type="classificationLevels" use="required"/>
        </xs:complexType>
    </xs:element>
    <xs:simpleType name="classificationLevels">
        <xs:restriction base="xs:string">
            <xs:enumeration value="top-secret"/>
            <xs:enumeration value="secret"/>
            <xs:enumeration value="confidential"/>
            <xs:enumeration value="unclassified"/>
        </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="paraType">
        <xs:restriction base="xs:string">
            <xs:maxLength value="200"/>
            <xs:pattern value="[\sa-zA-Z0-9,;:\.]*"/>
        </xs:restriction>
    </xs:simpleType>
</xs:schema>