[exim] failed: condition name expected, but found ""

I must be misunderstanding the documentation or the log error below.

I have this condition in my smtp transport.

transport_filter = ${if match_address{$sender_address}{myfromaddress@somedomain}{/bin/mycmd}}

I get this error in the log:

LOG: MAIN
== recipient@??? R=dnslookup T=remote_smtp defer (0): Expansion of "${if" from command "${if match_address{$sender_address}{myfromaddress@somedomain}{/sbin/mycmd}}" in remote_smtp transport failed: condition name expected, but found ""
>>>>>>>>>>>>>>>> deliveries are done >>>>>>>>>>>>>>>>

"match_address" is listed under Expansion Conditions but that must
not be what a "condition name" is?

What am I doing wrong?

Wayne