[rules-users] cannot import function

HI,all: i want import an function in another drools file. but when i use "import function " in drools 5.3.0.Final compile give me a error message: Rule Compilation error : [Rule name='start'] room/Rule_start.java (2:279) : Only a type can be imported. util.convertString2Set resolves to a package room/Rule_start.java (9:629) : The method convertString2Set(String) is undefined for the type Rule_start and i search in google not find any help . -- View this message in context: http://drools.46999.n3.nabble.com/cannot-import-function-tp3668460p366846... Sent from the Drools: User forum mailing list archive at Nabble.com.