check before removing (obsolete?) books param from dict

openlibrary/plugins/search/code.py

@@ -477,7 +477,8 @@ def _lookup_1(self, i, query, offset, rows):
                     ak = web.ctx.site.get(a["key"])
                     if ak:
                         akd = ak.dict()
-                        del akd['books']
+                        if 'books' in akd:
+                            del akd['books']
                         a["expanded"] = akd
 
             dval["expanded_result"] = eresult