diff --git a/README.rst b/README.rst
index c36d7c6..900ef3c 100644
--- a/README.rst
+++ b/README.rst
@@ -14,9 +14,9 @@ This module is for Python 3.6 and above!
 INSTALLATION
 ============================
 
-You can install the package with pip:
+You can install the package with pip::
 
-    pip install py3-validate-email
+    python -m pip install py3-validate-email
 
 
 USAGE
@@ -45,20 +45,20 @@ The function :code:`validate_email_or_fail()` works exactly like :code:`validate
 
 Auto-updater
 ============================
-The package contains an auto-updater for downloading and updating the built-in blacklist.txt. It will run on each module load (and installation), but will try to update the content if the file is older than 5 days, and if the content is not the same that's already downloaded.
+The package contains an auto-updater for downloading and updating the built-in blacklist.txt. It will run on each module load (and installation), but will try to update the content only if the file is older than 5 days, and if the content is not the same that's already downloaded.
 
 The update can be triggered manually::
 
     from validate_email.updater import update_builtin_blacklist
 
     update_builtin_blacklist(force: bool = False, background: bool = True,
-        callback: MethodType = None) -> Optional[Thread]
+        callback: Callable = None) -> Optional[Thread]
 
 :code:`force`: forces the update even if the downloaded/installed file is fresh enough.
 
 :code:`background`: starts the update in a ``Thread`` so it won't make your code hang while it's updating. If you set this to true, the function will return the Thread used for starting the update so you can ``join()`` it if necessary.
 
-:code:`callback`: An optional function to be called when the update is done.
+:code:`callback`: An optional `Callable` (function/method) to be called when the update is done.
 
 TODOs and BUGS
 ============================
diff --git a/validate_email/updater.py b/validate_email/updater.py
index 04a7728..d0bf06c 100644
--- a/validate_email/updater.py
+++ b/validate_email/updater.py
@@ -4,8 +4,7 @@ from pathlib import Path
 from tempfile import gettempdir, gettempprefix
 from threading import Thread
 from time import time
-from types import MethodType
-from typing import Optional
+from typing import Callable, Optional
 from urllib.error import HTTPError
 from urllib.request import Request, urlopen
 
@@ -36,7 +35,7 @@ class BlacklistUpdater(object):
     """
 
     _refresh_when_older_than: int = 5 * 24 * 60 * 60  # 5 days
-    _on_update_callback: MethodType = None
+    _on_update_callback: Callable = None
     _is_install_time: bool = False
 
     @property
@@ -123,11 +122,11 @@ class BlacklistUpdater(object):
                 BLACKLIST_FILEPATH_TMP.touch()
                 return
             raise
-        if type(self._on_update_callback) is MethodType:
+        if self._on_update_callback:
             self._on_update_callback()
 
     def process(
-            self, force: bool = False, callback: Optional[MethodType] = None):
+            self, force: bool = False, callback: Optional[Callable] = None):
         'Start optionally updating the blacklist.txt file.'
         # Locking to avoid multi-process update on multi-process startup
         self._on_update_callback = callback
@@ -137,7 +136,7 @@ class BlacklistUpdater(object):
 
 def update_builtin_blacklist(
         force: bool = False, background: bool = True,
-        callback: MethodType = None) -> Optional[Thread]:
+        callback: Callable = None) -> Optional[Thread]:
     """
     Update and reload the built-in blacklist. Return the `Thread` used
     to do the background update, so it can be `join()`-ed.