<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema elementFormDefault="qualified" xmlns:xsd="http://www.w3.org/2001/XMLSchema">

    <xsd:include schemaLocation="baseTypes.xsd" />

    <xsd:element name="types" type="typesType">
        <xsd:key name="typeKey">
            <xsd:selector xpath="type"/>
            <xsd:field xpath="@id"/>
        </xsd:key>
    </xsd:element>

    <xsd:complexType name="typesType">
        <xsd:sequence>
            <xsd:element name="type" type="typeType" minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
        <xsd:attribute name="version" use="optional">
            <xsd:simpleType>
                <xsd:restriction base="xsd:string">
                    <xsd:pattern value="\d+.\d+"></xsd:pattern>
                </xsd:restriction>
            </xsd:simpleType>
        </xsd:attribute>
    </xsd:complexType>

</xsd:schema>
