class_docstr: Base class for shelf implementations.
  
  This is initialized with a dictionary-like object.
  See the module's __doc__ string for an overview of the interface.
class_docstr_tok: ["Base","class","for","shelf","implementations",".","This","is","initialized","with","a","dictionary-like","object",".","See","the","module","'s","__doc__","string","for","an","overview","of","the","interface","."]
code: def __len__(self):
      return len(self.dict)
  
imports: from pickle import DEFAULT_PROTOCOL, Pickler, Unpickler
  from io import BytesIO
  import collections.abc
label_desc: Use image node_id 3 for calling the Shelf obj's underlying member method code with example usage: obj.__len__() and returns: len