Implementation:Scikit learn Scikit learn Deprecation

Knowledge Sources	Scikit_learn Scikit-learn Docs
Domains	Machine Learning, API Design
Last Updated	2026-02-08 15:00 GMT

Overview

Concrete tool for marking functions, classes, and properties as deprecated with warning messages, provided by scikit-learn.

Description

The deprecated class is a decorator that marks a function, class, or property as deprecated. When the decorated object is used, it issues a FutureWarning and appends a deprecation notice to the docstring. It supports decorating classes (wrapping __init__), properties, and regular functions, with an optional extra message.

Usage

Use this decorator when you need to deprecate a function, class, or property in scikit-learn's API. It ensures users are warned about upcoming removals and provides guidance on alternatives.

Code Reference

Source Location

• Repository: scikit-learn
• File: sklearn/utils/deprecation.py

Signature

class deprecated:
    def __init__(self, extra=""):
    def __call__(self, obj):
    def _decorate_class(self, cls):
    def _decorate_property(self, prop):
    def _decorate_fun(self, fun):

Import

from sklearn.utils import deprecated

I/O Contract

Inputs

Name	Type	Required	Description
extra	str	No	Additional message appended to the deprecation warning (default )
obj	class, function, or property	Yes	The object to be marked as deprecated (passed via decorator syntax)

Outputs

Name	Type	Description
wrapped	class, function, or property	The wrapped object that issues deprecation warnings when used

Usage Examples

Basic Usage

from sklearn.utils import deprecated

@deprecated("Use new_function instead.")
def old_function():
    return "result"

old_function()  # Issues FutureWarning: Function old_function is deprecated. Use new_function instead.

Related Pages

• Principle:Scikit_learn_Scikit_learn_Model_Instantiation