I have a sequence and want to know whether there are duplicate values in it.

I came out with the following and think there must be an easy solution. Any suggestion?

let $sequence :=(1,12,14,17,22,12) return (count(distinct-values($sequence)) ne count($sequence))

<xsl:function name="functx:are-distinct-values" as="xs:boolean"
              xmlns:functx="http://www.functx.com">
  <xsl:param name="seq" as="xs:anyAtomicType*"/>

  <xsl:sequence select="
   count(distinct-values($seq)) = count($seq)
 "/>