[exim] Running a command in a ACL?

I want to be able to run a command in a ACL.  So in the example below If the ratelimit is hit I want to add the sender_host_address to a file.  This example below I have pieced together from google and reading the documents but it doesn't seem to work.  What am I doing wrong?
warn        ratelimit = 1 / 5m / strict        condition = ${run{/bin/sh -c "echo ${sender_host_address} >> /usr/local/etc/exim/ratelimited_hosts"}{0}{1}}