[basex-talk] Determining whether a function exists

Howdy -- I'm trying to determine whether sql:execute-prepared exists, to have a module that functions in both BaseX 7.3 and 7.5. However -- exists(function-lookup(xs:QName("sql:execute-prepared"), 2)) returns false even in BaseX 7.5, even though function-name(function-lookup(xs:QName("sql:execute-prepared"), 2)) properly returns "sql:execute-prepared". Am I going to have to use a try block to detect this case?