From 2ba347841ac917d6c5ba48e7ffb46b82e38d7a7a Mon Sep 17 00:00:00 2001
From: Tim Head <betatim@gmail.com>
Date: Mon, 5 Sep 2016 22:26:38 +0200
Subject: [PATCH] Keep abstractmethod decorator

---
 sklearn/metrics/scorer.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sklearn/metrics/scorer.py b/sklearn/metrics/scorer.py
index 4b39d8ec58bb6..324c3ce6587c7 100644
--- a/sklearn/metrics/scorer.py
+++ b/sklearn/metrics/scorer.py
@@ -18,7 +18,7 @@
 #          Arnaud Joly <arnaud.v.joly@gmail.com>
 # License: Simplified BSD
 
-from abc import ABCMeta
+from abc import ABCMeta, abstractmethod
 import warnings
 
 import numpy as np
@@ -39,9 +39,10 @@ def __init__(self, score_func, sign, kwargs):
         self._score_func = score_func
         self._sign = sign
         # XXX After removing the deprecated scorers (v0.20) remove the
-        # XXX deprecation_msg property again and make __call__ abstract again
+        # XXX deprecation_msg property again and remove __call__'s body again
         self._deprecation_msg = None
 
+    @abstractmethod
     def __call__(self, estimator, X, y, sample_weight=None):
         if self._deprecation_msg is not None:
             warnings.warn(self._deprecation_msg,