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