diff --git a/swh/__init__.py b/swh/__init__.py
index f14e196529632bc4e37f7e7deb0b49db4742a423..e780381ceb98b03e44464c5ccdc01a7f3d5a8a63 100644
--- a/swh/__init__.py
+++ b/swh/__init__.py
@@ -1,4 +1,4 @@
 from pkgutil import extend_path
 from typing import Iterable
 
-__path__ = extend_path(__path__, __name__)  # type: Iterable[str]
+__path__: Iterable[str] = extend_path(__path__, __name__)
diff --git a/swh/graph/cli.py b/swh/graph/cli.py
index 9ea61adf2b37d1dfb3a7205c48e08885cfdc396a..07a75d232e8f909090c4cb98e74ada12d688d875 100644
--- a/swh/graph/cli.py
+++ b/swh/graph/cli.py
@@ -31,7 +31,7 @@ class PathlibPath(click.Path):
         return Path(super().convert(value, param, ctx))
 
 
-DEFAULT_CONFIG = {"graph": ("dict", {})}  # type: Dict[str, Tuple[str, Any]]
+DEFAULT_CONFIG: Dict[str, Tuple[str, Any]] = {"graph": ("dict", {})}
 
 
 @click.group(name="graph", context_settings=CONTEXT_SETTINGS, cls=AliasedGroup)
diff --git a/swh/graph/webgraph.py b/swh/graph/webgraph.py
index 291c04df44bb0f8363670730d0a8dec276b7f251..254803aba78b03e29cfa4994570999b7e626a5fe 100644
--- a/swh/graph/webgraph.py
+++ b/swh/graph/webgraph.py
@@ -45,7 +45,7 @@ COMP_SEQ = list(CompressionStep)
 # specified here as lists of tokens that will be joined together only for ease
 # of line splitting. In commands, {tokens} will be interpolated with
 # configuration values, see :func:`compress`.
-STEP_ARGV = {
+STEP_ARGV: Dict[CompressionStep, List[str]] = {
     CompressionStep.MPH: [
         "{java}",
         "it.unimi.dsi.sux4j.mph.GOVMinimalPerfectHashFunction",
@@ -133,7 +133,7 @@ STEP_ARGV = {
         "{out_dir}/{graph_name}-bv.offsets",
         "{tmp_dir}",
     ],
-}  # type: Dict[CompressionStep, List[str]]
+}
 
 
 class StepOption(ParamType):
@@ -147,7 +147,7 @@ class StepOption(ParamType):
     name = "compression step"
 
     def convert(self, value, param, ctx) -> Set[CompressionStep]:
-        steps = set()  # type: Set[CompressionStep]
+        steps: Set[CompressionStep] = set()
 
         specs = value.split(",")
         for spec in specs: