code: def size(self):
      return sum(os.path.getsize(f) for f in self.values())
  
imports: import os
  import gc
  import pickle
  import lore
  from lore.stores.base import Base
  from lore.util import timer
  from lore.env import require
  import pandas
  from datetime import datetime
label_desc: Use image node_id 9 for calling the Disk obj's underlying member method code with example usage: obj.size() and returns: sum