changed as notmuch has evolved but the following should work on all
versions of notmuch from 0.13 on. These functions take a list of
tag changes as argument. For example, an argument of (list "+spam"
-"-inbox) adds the tag spam and deletes the tag inbox. Note the
+"-inbox") adds the tag spam and deletes the tag inbox. Note the
argument must be a list even if there is only a single tag change
e.g., use (list "+deleted") to add the deleted tag.