def from_xml(cls, xml_tree):
arena = Arena()
locs = []
rooms = []
doors = []
for child in xml_tree.getchildren():
if child.tag == 'LOCATION':
locs.append(Location.from_xml(child))
elif child.tag == 'ROOM':
rooms.append(Room.from_xml(child))
elif child.tag == 'DOOR':
doors.append(Door.from_xml(child))
arena.locations = locs
arena.rooms = rooms
arena.doors = doors
return arena
