// parse.input: modified from po.xsd
            <xsd:schema xmlns:xsd="http://www.w3.org/2000/08/XMLSchema">

             // root element
             <xsd:element name="purchaseOrder" type="PurchaseOrderType"/>

            // <xsd:element name="comment" type="xsd:string"/>

             <xsd:complexType name="PurchaseOrderType">
              <xsd:sequence>
               <xsd:element name="shipTo" type="USAddress"/>
               <xsd:element name="billTo" type="USAddress"/>
               //<xsd:element ref="comment" minOccurs="0"/>
               <xsd:element name="items"  type="Items"/>
              </xsd:sequence>
             // <xsd:attribute name="orderDate" type="xsd:date"/>
             </xsd:complexType>

             <xsd:complexType name="USAddress">
              <xsd:sequence>
               <xsd:element name="name"   type="xsd:string"/>
               <xsd:element name="street" type="xsd:string"/>
               <xsd:element name="city"   type="xsd:string"/>
               <xsd:element name="state"  type="xsd:string"/>
               <xsd:element name="zip"    type="xsd:string"/> //decimal"/>
              </xsd:sequence>
             // <xsd:attribute name="country" type="xsd:string"/>
             </xsd:complexType>

             <xsd:complexType name="Items">
              <xsd:sequence>
               <xsd:element name="item" type="Item" minOccurs="0" maxOccurs="5"/> 
              </xsd:sequence>
             </xsd:complexType> 

             <xsd:complexType name="Item">
              <xsd:sequence>
               <xsd:element name="productName" type="xsd:string"/>
               <xsd:element name="quantity" type="QuantityType"/>
               <xsd:element name="USPrice"    type="xsd:decimal"/>
               <xsd:element name="shipDate" type="xsd:date"/> 
              </xsd:sequence>
             // <xsd:attribute name="partNum" type="SKU"/>
             </xsd:complexType> 

             <xsd:simpleType name="QuantityType">
              <xsd:restriction base="xsd:positiveInteger">
               <xsd:minInclusive value= 1/>
               <xsd:maxInclusive value= 10/>
              </xsd:restriction>
             </xsd:simpleType>

           // <!-- Stock Keeping Unit, a code for identifying products -->
             <xsd:simpleType name="SKU">
              <xsd:restriction base="xsd:integer">
               <xsd:minInclusive value= 10000/>
               <xsd:maxInclusive value= 99999/>
              </xsd:restriction>
             </xsd:simpleType>

            </xsd:schema>