class_docstr: A property value container for ColumnData that supports change
  notifications on mutating operations.
  
  This property value container affords specialized code paths for
  updating the .data dictionary for ColumnDataSource. When possible,
  more efficient ColumnDataChangedEvent hints are generated to perform
  the updates:
  
  .. code-block:: python
  
      x[i] = y
      x.update
code: def __copy__(self):
      return PropertyValueColumnData(dict(self))
  
imports: from __future__ import annotations
  import logging
  import copy
  from typing import TYPE_CHECKING, Any, Iterable, TypeVar
  import numpy
label_desc: Use image node_id 2 for calling the PropertyValueColumnData obj's underlying member method code with example usage: obj.__copy__() and returns: PropertyValueColumnData