code: def __call__(self, table, filename):
      key = table, filename
      obj = self.__memo.get(key, None)
      if obj is None:
          obj = self.__memo[key] = self.new(table, filename)
      return obj
  
imports: import _symtable
  from _symtable import USE, DEF_GLOBAL, DEF_NONLOCAL, DEF_LOCAL, DEF_PARAM, DEF_IMPORT, DEF_BOUND, DEF_ANNOT, SCOPE_OFF, SCOPE_MASK, FREE, LOCAL, GLOBAL_IMPLICIT, GLOBAL_EXPLICIT, CELL
  import weakref
label_desc: Use image node_id 3 for calling the SymbolTableFactory obj's underlying member method code with example usage: obj.__call__(table, filename) and returns: obj