Problem with sed

[Jerry]

I rarely use sed, so I admit to not being fully acquainted with its
idiosyncrasies,; however, this one is really annoying.

I am using this command in an attempt to remove empty lines:

$ sed -i /^$/d /var/tmp/myfile.txt

and get this error:

sed: 1: "/var/tmp/myfile.txt": undefined label 'mp/myfile.txt'

I don't understand why. I am following the example I found in the "sed & awk" handbook by "O'Reilly"
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