class_docstr: Statistic tracking only the number of samples.
  
  For example::
  
      >>> stats = CountStats()
      >>> stats.update(torch.randn(3, 3))
      >>> stats.get()
      {'count': 1}
code: def __init__(self):
      self.count = 0
      super().__init__()
  
imports: import copy
  from abc import ABC, abstractmethod
  from collections import defaultdict
  from typing import Any, Callable, Dict, Hashable, Union
  import torch
  from pyro.ops.welford import WelfordCovariance
label_desc: Use image node_id 1 to create a new CountStats object from inherited base classes: StreamingStats with example: obj = CountStats()