Either BASIC-STRUCTURE-REF or BASIC-STRUCTURE-SNREF is required for END-OF-PDU-FIELD

[premkumar-masilamani]

Removed the assert statement that expects BASIC-STRUCTURE-REF to be present for all the END-OF-PDU-FIELD.

Sample ODX-D file snippet, with the first field having BASIC-STRUCTURE-REF and the second having BASIC-STRUCTURE-SNREF

            <END-OF-PDU-FIELD ID="id-153db528-e63b-42d8-9c11-7847b8eddebf">
              <SHORT-NAME>DataIdentifierResponseField</SHORT-NAME>
              <LONG-NAME>Data Identifier Response Field</LONG-NAME>
              <BASIC-STRUCTURE-REF ID-REF="id-f155f44d-1fad-4b49-bc56-3ad2a5f63bbf"/>
              <MAX-NUMBER-OF-ITEMS>4</MAX-NUMBER-OF-ITEMS>
              <MIN-NUMBER-OF-ITEMS>1</MIN-NUMBER-OF-ITEMS>
            </END-OF-PDU-FIELD>

            <END-OF-PDU-FIELD ID="id-af7fba3d-9a2a-4b12-88c4-810f529457ca">
              <SHORT-NAME>PeriodicIdentifierRequestField</SHORT-NAME>
              <LONG-NAME>Periodic Identifier Request Field</LONG-NAME>
              <BASIC-STRUCTURE-SNREF SHORT-NAME="PeriodicIdentifierRequestStructure"/>
              <MAX-NUMBER-OF-ITEMS>4</MAX-NUMBER-OF-ITEMS>
              <MIN-NUMBER-OF-ITEMS>1</MIN-NUMBER-OF-ITEMS>
            </END-OF-PDU-FIELD>

Corresponding XSD snippet

                    <xsd:choice maxOccurs="1" minOccurs="1">
                        <xsd:element name="BASIC-STRUCTURE-REF" type="ODXLINK"/>
                        <xsd:element name="BASIC-STRUCTURE-SNREF" type="SNREF"/>
                    </xsd:choice>

[andlaus]

thanks. your patch is obviously correct. That said, I'll wait with merging until I've fixed the newly appearing typechecking errors due to mypy 0.99. (PR for this is in the making, it will probably be opened today or tomorrow.)

[andlaus]

ok, #89 has been merged. this can now go in as well. Thanks for the catch!