`
<xsd:schema xmlns="http://www.example.com/schema-a"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:schema-b="http://www.example.com/schema-b"
targetNamespace="http://www.example.com/schema-a"
elementFormDefault="qualified">
<xsd:import schemaLocation="schema-b.xsd" namespace="http://www.example.com/schema-b"/>
<xsd:complexType name="exampleType">
    <xsd:sequence>
        <xsd:element name="property-a" type="xsd:positiveInteger" minOccurs="0"/>
        <xsd:element ref="schema-b:example-element" minOccurs="0"/>
    </xsd:sequence>
</xsd:complexType>
</xsd:schema>
`
`
<xsd:schema xmlns="http://www.example.com/schema-b"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://www.example.com/schema-b"
elementFormDefault="qualified">
<xsd:element name="example-element" >
    <xsd:complexType>
        <xsd:sequence>
            <xsd:choice>
                <xsd:sequence>
                    <xsd:element name="element-a" type="xsd:string"/>
                    <xsd:element name="element-b" type="xsd:string" minOccurs="0"/>
                </xsd:sequence>
                <xsd:element name="element-b" type="xsd:string"/>
            </xsd:choice>
            <xsd:element name="blah" type="xsd:string"/>
        </xsd:sequence>
    </xsd:complexType>
</xsd:element>
</xsd:schema>
`
How to simplify the choice in example-element. Adding binding or directly in the schema results in the error from the title.