diff --git a/stegano/steganalysis/statistics.py b/stegano/steganalysis/statistics.py
index b83ab31..985ecf1 100644
--- a/stegano/steganalysis/statistics.py
+++ b/stegano/steganalysis/statistics.py
@@ -25,6 +25,7 @@ __date__ = "$Date: 2010/10/01 $"
 __revision__ = "$Date: 2016/08/26 $"
 __license__ = "GPLv3"
 
+import typing
 import operator
 
 from PIL import Image
@@ -37,7 +38,7 @@ def steganalyse(img):
     """
     encoded = img.copy()
     width, height = img.size
-    colours_counter = Counter() # type: Counter[int]
+    colours_counter = Counter() # type: typing.Counter[int]
     for row in range(height):
         for col in range(width):
             r, g, b = img.getpixel((col, row))
diff --git a/tools/run_mypy.py b/tools/run_mypy.py
index c70e6da..7a1efc2 100644
--- a/tools/run_mypy.py
+++ b/tools/run_mypy.py
@@ -1,18 +1,21 @@
 import subprocess
 import sys
 
-modules = ["stegano/tools.py",
-            "stegano/lsb/lsb.py",
-            "stegano/lsbset/lsbset.py",
-            "stegano/lsbset/generators.py",
-            "stegano/red/red.py",
-            "stegano/exifHeader/exifHeader.py",
-            "stegano/steganalysis/parity.py",
-            "stegano/steganalysis/statistics.py"]
+modules = ['stegano/tools.py',
+           'stegano/lsb/lsb.py',
+           'stegano/lsbset/lsbset.py',
+           'stegano/lsbset/generators.py',
+           'stegano/red/red.py',
+           'stegano/exifHeader/exifHeader.py',
+           'stegano/steganalysis/parity.py',
+           'stegano/steganalysis/statistics.py']
 
 exit_codes = []
 for module in modules:
-    rc = subprocess.call(["mypy", "--ignore-missing-imports",
-                          "--follow-imports", "skip", module])
+    rc = subprocess.call(['mypy', '--ignore-missing-imports',
+                          '--check-untyped-defs',
+                          '--follow-imports', 'skip', module],
+                          )
     exit_codes.append(rc)
+
 sys.exit(max(exit_codes))