returns the result of interpreting the object as an instance of ` book ' . this implementation returns null ; returning a non-null result will terminate the switch . concode_field_sep HbmapkeysPackage modelPackage concode_field_sep T caseStringToWriterMapEntry concode_elem_sep T doSwitch concode_elem_sep T doSwitch concode_elem_sep T doSwitch concode_elem_sep T caseCity concode_elem_sep T caseWriterToCityMapEntry concode_elem_sep T caseWriter concode_elem_sep T defaultCase
T function ( Book arg0 ) { return null ; }