def get_actor_and_actant (cls, root_node):
idx = 0
actor = None
actant = None
while idx < len (root_node.children):
child = root_node.children[idx]
if child.type == PropositionTreeNodeType.linkage:
if child.linkage.name == LanguageHelper.translate ("who") or child.linkage.name == LanguageHelper.translate ("what"):
parent = child
child = child.children[0]
if child.type == PropositionTreeNodeType.concept:
if child.side == PropositionTreeNodeSide.left:
actor = child
if root_node.concept.subroot != True:
ContextProvider.set_actor_node (actor)
elif child.side == PropositionTreeNodeSide.right:
actant = child
if actor != None and actant != None:
break
idx += 1
if actor == None:
actor = ContextProvider.get_actor_node ()
return actor, actant
