# File lib/ruote/extract.rb, line 96
  def self.extract_wfid(o)

    return o.strip == '' ? nil : o if o.is_a?(String)
    return o.wfid if o.respond_to?(:wfid)
    return o['wfid'] || o.fetch('fei', {})['wfid'] if o.respond_to?(:[])
    nil
  end