class_docstr: Insert FutureWarning for object creation
  
  Examples
  --------
  >>> class C: pass
  >>> class D(FutureWarningMixin, C):
  ...     warn_message = "Please, don't use this class"
  
  Record the warning
  
  >>> with warnings.catch_warnings(record=True) as warns:
  ...     d = D()
  ...     warns[0].message.args[0]
  "Please, don't use this class"
code: def __init__(self, *args: P.args, **kwargs: P.kwargs) -> None:
      warnings.warn(self.warn_message, FutureWarning, stacklevel=2)
      super().__init__(*args, **kwargs)
  
file_path: nibabel/nibabel/deprecated.py
imports: from __future__ import annotations
  import typing
  import warnings
  from .deprecator import Deprecator
  from .pkg_info import cmp_pkg_version
label_desc: Use image node_id 1 to create a new FutureWarningMixin object  with example: obj = FutureWarningMixin()