def lookup(key, container_lookup=false)

      Ruote.lookup(h.fields, key, container_lookup)
    end
def lookup(key, container_lookup=false)

      Ruote.lookup(h.fields, key, container_lookup)
    end
Warning : hash is fei's hash.

 For a simple key

   workitem.lookup('toto')

 is equivalent to

   workitem.fields['toto']

 but for a complex key

   workitem.lookup('toto.address')

 is equivalent to

   workitem.fields['toto']['address']