findclass tcl ERR on no entry found

Any idea why findclass would throw an error on no entry found instead of just not returning a value...?

I'm working around by using catch to keep it from erroring out, but is this expected behavuiour?

set row [findclass [getfield [HTTP::host] ":" 1]:[TCP::local_port] $::myRedirects]

results in this error:"ERR: No entry for company.com in myRedirects class"

TIA

/deb