Defined in file macro.asn C++ class: CField_pair_type Field-pair-type ::= CHOICE { source-qual Source-qual-pair , feature-field Feature-field-pair , rna-field Rna-qual-pair , cds-gene-prot CDSGeneProt-field-pair , molinfo-field Molinfo-field-pair , struc-comment-field Structured-comment-field-pair , dblink DBLink-field-pair}