diff --git a/pyproject.toml b/pyproject.toml
index 872397bb..340ad041 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -194,3 +194,8 @@ quote-style = "double"
 [tool.ty.src]
 include = ["src", "tests"]
 exclude = ["src/torchjd/aggregation/_nash_mtl.py"]
+
+[tool.ty.rules]
+# nn.Module declares `forward` as a mutable `Callable[..., Any]` attribute, so every
+# `forward` override would be flagged.
+invalid-mutable-override = "ignore"
diff --git a/tests/trajectories/_plotters.py b/tests/trajectories/_plotters.py
index 47078da4..21b8157c 100644
--- a/tests/trajectories/_plotters.py
+++ b/tests/trajectories/_plotters.py
@@ -5,7 +5,7 @@
 
 import matplotlib.patheffects as pe
 import numpy as np
-from matplotlib import cm as cm, colors as mcolors, pyplot as plt
+from matplotlib import colormaps, colors as mcolors, pyplot as plt
 from numpy.lib.stride_tricks import sliding_window_view
 
 Color: TypeAlias = str | tuple[float, float, float] | tuple[float, float, float, float]
@@ -128,7 +128,7 @@ class ContourCirclesPlotter(MultiPlotter):
 
     def __init__(self) -> None:
         radiuses = [1.0, 2.5, 4, 5.5, 7, 8.5]
-        colormap = cm.inferno_r
+        colormap = colormaps["inferno_r"]
         norm = mcolors.Normalize(vmin=-1, vmax=max(radiuses))
         plotters = tuple(CirclePlotter(radius, colormap(norm(radius))) for radius in radiuses)
         super().__init__(plotters)