Update whatsnew and fix pep8 issue

doc/source/whatsnew/v0.19.2.txt

@@ -22,6 +22,7 @@ Performance Improvements
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
 - Improved performance of ``.replace()`` (:issue:`12745`)
+- Improved performance ``Series`` creation with a datetime index and dictionary data (:issue:`14894`)
 
 .. _whatsnew_0192.enhancements.other:
 

pandas/core/series.py

@@ -188,7 +188,8 @@ class Series(base.IndexOpsMixin, strings.StringAccessorMixin,
                         if len(data):
                             # coerce back to datetime objects for lookup
                             data = _dict_compat(data)
-                            data = lib.fast_multiget(data, index.asobject.values,
+                            data = lib.fast_multiget(data,
+                                                     index.asobject.values,
                                                      default=np.nan)
                         else:
                             data = np.nan