<xs:attribute name="companyName" use="required" type="xs:string"><xs:annotation><xs:documentation>companyName: Name of the company</xs:documentation></xs:annotation></xs:attribute>
<xs:attribute name="scheme" use="required" type="xs:string"><xs:annotation><xs:documentation>isin: ISIN of the company (this is common for a company listed across multiple exchanges)</xs:documentation></xs:annotation></xs:attribute>