<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    
    <xsd:element name="a" type="SubscriptionReqElement" />
    <xsd:element name="b" type="DescriptionElement" />
    
    <xsd:complexType name="Interval">
        <xsd:attribute name="min" type="xsd:short" use="required"/>
        <xsd:attribute name="max" type="xsd:short" use="required"/>
    </xsd:complexType>
    
    <xsd:complexType name="SubscriptionReqElement">
        <xsd:choice>
            <xsd:element name="interval" type="Interval"/>
        </xsd:choice>
        <xsd:attribute name="id" type="xsd:short" use="required"/>
    </xsd:complexType>
    
    <xsd:complexType name="DescriptionElement">
        <xsd:sequence>
            <xsd:element name="interval" type="Interval"/>
        </xsd:sequence>
        <xsd:attribute name="id" type="xsd:short" use="required"/>
        <xsd:attribute name="name" type="xsd:string" use="required"/>
    </xsd:complexType>
    
</xsd:schema>