DEPR: provide deprecations and exposure for NaTType (pandas-dev#16146)

xref pandas-dev#16137

Author: jreback

doc/source/whatsnew/v0.20.0.txt

@@ -1246,7 +1246,7 @@ these are now the public subpackages.
 
 
 - The function :func:`~pandas.api.types.union_categoricals` is now importable from ``pandas.api.types``, formerly from ``pandas.types.concat`` (:issue:`15998`)
-
+- The type import ``pandas.tslib.NaTType`` is deprecated and can be replaced by using ``type(pandas.NaT)`` (:issue:`16146`)
 
 .. _whatsnew_0200.privacy.errors:
 

pandas/__init__.py

@@ -77,6 +77,7 @@
                           moved={'Timestamp': 'pandas.Timestamp',
                                  'Timedelta': 'pandas.Timedelta',
                                  'NaT': 'pandas.NaT',
+                                 'NaTType': 'type(pandas.NaT)',
                                  'OutOfBoundsDatetime': 'pandas.errors.OutOfBoundsDatetime'})
 
 # use the closest tagged version if possible

pandas/tslib.py

@@ -4,4 +4,4 @@
 warnings.warn("The pandas.tslib module is deprecated and will be "
               "removed in a future version.", FutureWarning, stacklevel=2)
 from pandas._libs.tslib import (Timestamp, Timedelta,
-                               NaT, OutOfBoundsDatetime)
+                               NaT, NaTType, OutOfBoundsDatetime)