diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 7a0757a991..6d712ec8a8 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -84,10 +84,8 @@ repos:
     # These also need to be removed in setup.cfg
     exclude: |
       (?x)(
-        ^hoomd/hpmc/external/wall.py|
         ^hoomd/extern/|
         ^hoomd/mpcd/|
-        ^hoomd/dem/|
         ^hoomd/metal/
       )
 - repo: https://github.com/pre-commit/mirrors-clang-format
diff --git a/hoomd/hpmc/external/user.py b/hoomd/hpmc/external/user.py
index 103f9209dd..c188a372a6 100644
--- a/hoomd/hpmc/external/user.py
+++ b/hoomd/hpmc/external/user.py
@@ -74,9 +74,9 @@ class CPPExternalPotential(ExternalField):
     Example:
         .. code-block:: python
 
-            grav_code = "return r_i.z + box.getL().z/2;"
+            gravity_code = "return r_i.z + box.getL().z/2;"
             gravity = hoomd.hpmc.external.user.CPPExternalPotential(
-                code=grav_code)
+                code=gravity_code)
             mc.external_potential = gravity
 
     Note:
diff --git a/hoomd/hpmc/external/wall.py b/hoomd/hpmc/external/wall.py
index ecd2d03a14..0d134277f2 100644
--- a/hoomd/hpmc/external/wall.py
+++ b/hoomd/hpmc/external/wall.py
@@ -1,9 +1,14 @@
 # Copyright (c) 2009-2022 The Regents of the University of Michigan.
 # Part of HOOMD-blue, released under the BSD 3-Clause License.
 
+"""Wall potentials HPMC simulations.
+
+Set :math:`U_{\\mathrm{external},i}` evaluated in
+`hoomd.hpmc.integrate.HPMCIntegrator` to a hard particle-wall interaction.
+"""
+
 import hoomd
 from hoomd.wall import _WallsMetaList
-from hoomd.data.parameterdicts import ParameterDict
 from hoomd.data.syncedlist import identity
 from hoomd.hpmc.external.field import ExternalField
 from hoomd.logging import log
@@ -24,7 +29,7 @@ def _to_hpmc_cpp_wall(wall):
 
 
 class _HPMCWallsMetaList(_WallsMetaList):
-    """Handle HPMC walls
+    """Handle HPMC walls.
 
     This class supplements the base `_WallsMetaList` class with the
     functionality to ensure that walls added to the `WallPotential` are
diff --git a/setup.cfg b/setup.cfg
index 82deae961a..43197363be 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -38,8 +38,6 @@ exclude = .git,
     __pycache__,
     build,
     hoomd/extern,
-    hoomd/hpmc/external/wall.py
-    hoomd/dem,
     hoomd/metal,
     hoomd/mpcd,
 max_line_length = 80