diff --git a/docker/test/integration/runner/Dockerfile b/docker/test/integration/runner/Dockerfile
index 1aad2ae6770..bd062296411 100644
--- a/docker/test/integration/runner/Dockerfile
+++ b/docker/test/integration/runner/Dockerfile
@@ -58,6 +58,7 @@ RUN apt-get update \
 
 RUN dockerd --version; docker --version
 
+# Architecture of the image when BuildKit/buildx is used
 ARG TARGETARCH
 # FIXME: psycopg2-binary is not available for aarch64, we skip it for now
 RUN test x$TARGETARCH = xarm64 || ( python3 -m pip install \
diff --git a/tests/ci/docker_manifests_merge.py b/tests/ci/docker_manifests_merge.py
index c6814b911ff..82d012bfe1a 100644
--- a/tests/ci/docker_manifests_merge.py
+++ b/tests/ci/docker_manifests_merge.py
@@ -57,7 +57,7 @@ def parse_args() -> argparse.Namespace:
 
     args = parser.parse_args()
     if len(args.suffixes) < 2:
-        raise parser.error("more than two --suffix should be given")
+        parser.error("more than two --suffix should be given")
 
     return args
 
@@ -81,6 +81,7 @@ def strip_suffix(suffix: str, images: Images) -> Images:
 
 
 def check_sources(to_merge: Dict[str, Images]) -> Images:
+    """get a dict {arch1: Images, arch2: Images}"""
     result = {}  # type: Images
     first_suffix = ""
     for suffix, images in to_merge.items():