message: Fix calculation of IE ratio for covent tests.
  Oops.
  GPC: covent-ie-ratio
diff: @@ -122,7 +122,7 @@ Intended TV: {intended_tv} ml
  """
  sec_per_breath = 60 / rr
  - ie_ratio = inspiratory_time / sec_per_breath
  + ie_ratio = inspiratory_time / (sec_per_breath - inspiratory_time)
  vars = {
  "gui_bpm": rr,
  "gui_ie_ratio": round(ie_ratio, 2),
  