diff --git a/Dockerfile b/Dockerfile
index 447da8c..9c20a17 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,6 +6,6 @@ COPY verify_pr_lables.py /verify_pr_lables.py
 
 # Force stdin, stdout and stderr to be totally unbuffered.
 # This warranty the order of output messages send to the console
-ENV PYTHONUNBUFFERED 1
+ENV PYTHONUNBUFFERED=1
 
 ENTRYPOINT ["/verify_pr_lables.py"]
diff --git a/verify_pr_lables.py b/verify_pr_lables.py
index f7bc6a3..0457746 100755
--- a/verify_pr_lables.py
+++ b/verify_pr_lables.py
@@ -207,7 +207,7 @@ def get_env_var(env_var_name, echo_value=False):
     # If reviews are disable, exit with an error code.
     if pr_reviews_disabled:
         print('Exiting with an error code')
-        exit(1)
+        sys.exit(1)
 
     # If there has been already a request for changes due to the presence of
     # invalid labels, then we don't request changes again.
@@ -231,7 +231,7 @@ def get_env_var(env_var_name, echo_value=False):
     # If reviews are disable, exit with an error code.
     if pr_reviews_disabled:
         print('Exiting with an error code')
-        exit(1)
+        sys.exit(1)
 
     # If there has been already a request for changes due to missing a valid
     # label, then don't request changes again.
@@ -255,7 +255,7 @@ def get_env_var(env_var_name, echo_value=False):
     # If reviews are disable, exit without an error code.
     if pr_reviews_disabled:
         print('Exiting without an error code')
-        exit(0)
+        sys.exit(0)
 
     # If the latest review done was approved, then don't approved it again.
     if last_review_approved: