diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# Copyright (C) 2015-2020  The Software Heritage developers
+# Copyright (C) 2015-2022  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -17,22 +17,23 @@
     long_description = f.read()
 
 
-def parse_requirements(name=None):
-    if name:
-        reqf = "requirements-%s.txt" % name
-    else:
-        reqf = "requirements.txt"
-
+def parse_requirements(*names):
     requirements = []
-    if not path.exists(reqf):
-        return requirements
+    for name in names:
+        if name:
+            reqf = "requirements-%s.txt" % name
+        else:
+            reqf = "requirements.txt"
+
+        if not path.exists(reqf):
+            return requirements
 
-    with open(reqf) as f:
-        for line in f.readlines():
-            line = line.strip()
-            if not line or line.startswith("#"):
-                continue
-            requirements.append(line)
+        with open(reqf) as f:
+            for line in f.readlines():
+                line = line.strip()
+                if not line or line.startswith("#"):
+                    continue
+                requirements.append(line)
     return requirements
 
 
@@ -48,12 +49,12 @@
     author_email="swh-devel@inria.fr",
     url="https://forge.softwareheritage.org/diffusion/DGRPH",
     packages=find_packages(),
-    install_requires=parse_requirements() + parse_requirements("swh"),
+    install_requires=parse_requirements(None, "swh"),
     tests_require=parse_requirements("test"),
     setup_requires=["setuptools-scm"],
     use_scm_version=True,
     extras_require={
-        "testing": parse_requirements("test"),
+        "testing": parse_requirements("luigi", "test"),
         "luigi": parse_requirements("luigi"),
     },
     include_package_data=True,
diff --git a/swh/graph/luigi/origin_contributors.py b/swh/graph/luigi/origin_contributors.py
--- a/swh/graph/luigi/origin_contributors.py
+++ b/swh/graph/luigi/origin_contributors.py
@@ -14,7 +14,7 @@
 # WARNING: do not import unnecessary things here to keep cli startup time under
 # control
 from pathlib import Path
-from typing import Dict, List, Tuple
+from typing import Dict, Iterable, List, Tuple, cast
 
 import luigi
 
@@ -148,7 +148,8 @@
         # and escape(name)
         sha256_to_names: Dict[bytes, Tuple[bytes, str]] = {}
         with pyzstd.open(self.deanonymization_table_path, "rt") as fd:
-            csv_reader = csv.reader(fd)
+            # TODO: remove that cast once we dropped Python 3.7 support
+            csv_reader = csv.reader(cast(Iterable[str], fd))
             header = next(csv_reader)
             assert header == ["sha256_base64", "base64", "escaped"], header
             for line in csv_reader:
@@ -179,7 +180,8 @@
 
             # Open input for reads as CSV
             with pyzstd.open(self.origin_contributors_path, "rt") as input_fd:
-                csv_reader = csv.reader(input_fd)
+                # TODO: remove that cast once we dropped Python 3.7 support
+                csv_reader = csv.reader(cast(Iterable[str], input_fd))
                 header = next(csv_reader)
                 assert header == ["origin_SWHID", "person_id"], header
                 for (origin_swhid, person_id) in csv_reader: