flink sql hop????udaf????

[bigdata]

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    flink1.10.1????sql 
hop??????????udaf????????????????????????????????marge??????
org.apache.flink.table.api.ValidationException: Function class 
'com.autoai.cns.udaf.PercentileUDAF' does not implement at least one method 
named 'merge' which is public, not abstract and (in case of table functions) 
not static