diff --git a/mayan/apps/ocr/backends/__init__.py b/mayan/apps/ocr/backends/__init__.py
index 6c671fa564..f6e245ceb8 100644
--- a/mayan/apps/ocr/backends/__init__.py
+++ b/mayan/apps/ocr/backends/__init__.py
@@ -1,3 +1,3 @@
 class BackendBase(object):
-    def execute(input_filename, language=None):  # NOQA
+    def execute(self, input_filename, language=None):  # NOQA
         raise NotImplementedError
diff --git a/mayan/apps/ocr/lang/__init__.py b/mayan/apps/ocr/lang/__init__.py
index 52965545af..9a45b1aaab 100644
--- a/mayan/apps/ocr/lang/__init__.py
+++ b/mayan/apps/ocr/lang/__init__.py
@@ -1,3 +1,3 @@
 class BackendBase(object):
-    def check_word(word):
-        raise NotImplemented
+    def check_word(self, word):
+        raise NotImplementedError