You have attempted to declare your own function in one of the following namespaces:
http://www.w3.org/XML/1998/namespace (xml)
xml
http://www.w3.org/2001/XMLSchema (xs)
xs
http://www.w3.org/2001/XMLSchema-instance (xsi)
xsi
http://www.w3.org/2005/xpath-functions (fn)
fn
This is not permitted. Instead, use the prefix local, or declare a new namespace and prefix your function name with that namespace.
local
18.191.67.40