class_docstr: Holds statistics about a Pipeline run.
  
  Pipelines produce statistics on each call to `transform`.
  `Statistic` objects can be merged together to aggregate
  statistics over the course of many calls to `transform`.
  
  A `Statistic` also has a string name which is used during merging. Any two
  `Statistic` instances with the same name may be merged together. The name
  should also be informative about what the `Statistic` is measuring. Names
  do not need to be unique globally (outside of the `Pipeline` objects that
  produce them) because a `Pipeline` that returns statistics will prepend
  its own name, effectively creating a namespace for each `Pipeline`.
code: def __str__(self):
      return self._pretty_print(self.name)
  
imports: import abc
  import bisect
  import copy
  import tensorflow.compat.v1
label_desc: Use image node_id 6 for calling the Statistic obj's underlying member method code with example usage: obj.__str__() and returns: self