scala.xml.Node attribute method signature consistency

Hello,

I don't understand scala.xml.Node attribute method signature.

def attribute(uri: String, key: String): Option[Seq[Node]]

scaladoc indicate :
returns value of UnprefixedAttribute with given key in attributes, if it
exists,
otherwise null.

So I would expect this method to return an Option[UnprefixedAttribute]
but it
returns an Option[Seq[Node]] instead.

Does someone knows why ?

Thanks,
Lucien