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Hi all,

I am using ceilometer with arithmetic transformer to combine two meters. 
Here is an extract of my pipeline.yaml (it's just a dummy test)

sources:
     - name: disk_source
       interval: 600
       meters:
           - "disk.read.bytes"
           - "disk.read.requests"
           - "disk.write.bytes"
           - "disk.write.requests"
       sinks:
           - disk_sink
           - disk_read_write_sink

sinks:
     - name: disk_read_write_sink
       transformers:
           - name: "arithmetic"
             parameters:
                 target:
                     name: "disk.read.write.bytes"
                     unit: "B"
                     type: "cumulative"
                     expr: "2*$(disk.read.bytes) + 2*$(disk.write.bytes)"
       publishers:
           - rpc://


I get this error:
"Unable to perform calculation, not all of {_disk_write_bytes_ESC, 
_disk_read_bytes_ESC} are present"

Anyone using this transformer?

Thanks!

Claudio