Remove python unicode "u:" from string in YAQL

Hello. I’m in a stackstorm workflow trying to construct a dict object and pass it as a string to core.http.
Above action runs, but fails as the body has the ‘u’ for unicode embedded in front of all the values ( u\‘reason\’: u\‘reasoncode\’ …).

write_elastic:
  action: core.http
  input:
    url: "http://url:port/index/_doc/"
    method: POST
    body: '<% str( { "run_id"=> $.run_id, "results"=> $.results }) %>'
    headers:
      Content-Type: "application/json

How do I produce a string that does NOT have Python unicode encoding for the body?

Try something like the tojson filter

Thanks! That did it!

how to use tojson filter? would you please give an example?