class_docstr: Decorator that marks that an attribute of an instance should not be
  computed until needed, and that the value should be memoized.
  
  Lifted from quantopian/trading_calendars
class_docstr_tok: ["Decorator","that","marks","that","an","attribute","of","an","instance","should","not","be","computed","until","needed",",","and","that","the","value","should","be","memoized",".","Lifted","from","quantopian\/trading_calendars"]
code: def __init__(self, get):
      self._get = get
      self._cache = WeakKeyDictionary()
  
imports: import math
  import numpy
  import random
  import scipy.sparse
  import six
  import tensorflow
  from weakref import WeakKeyDictionary
  from .input_utils import create_tensorrec_dataset_from_sparse_matrix, create_tensorrec_dataset_from_tfrecord
label_desc: Use image node_id 1 to create a new lazyval object from inherited base classes: object with example: obj = lazyval(get)