Never ending story: how to check and remove empty fields, arrays etc

[jetnet]

season I
season II
season III

season IV (thanks to season III):

  ruby {
        # Initialize the suspects once:
        init => "SuspectFields = ['tags']"
        code => "
                SuspectFields.each do |field|
                        event.remove(field) if event.get('field').nil? or event.get('field').empty?
                end
        "
  }

to be continued...