<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="zzz" xmlns="zzz">
  <xsd:complexType name="xxx">
    <xsd:sequence>
      <xsd:element name="e" type="xsd:string" minOccurs="1" maxOccurs=<error>"0"</error>/>
    </xsd:sequence>
  </xsd:complexType>
</xsd:schema>