Count Furniture by Rooms

from collections import defaultdict

# Get Last Phase of the project 
all_phases = FilteredElementCollector(doc).OfClass(Phase).ToElements()
last_phase = list(all_phases)[-1] #Ensure correct phase here

# Get All Furniture
all_furniture        = FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_Furniture).WhereElementIsNotElementType().ToElements()

# Sort Furniture by Rooms
dict_furniture = defaultdict(int)
for furn in all_furniture:
    try:
        room = furn.Room[last_phase] # Get Room where furniture is placed in the last phase.
        dict_furniture[room.Id] += 1
    except:
        print('Furniture [{}] Has No Room in Phase : {}'.format(furn.Id, last_phase.Name))


# Print Results
for room_id, count in dict_furniture.items():
	room = doc.GetElement(room_id)
	if room: print(room.Name, count)
	else:    print("No Room: {}".format(count))