diff --git a/python/lsst/pipe/tasks/background.py b/python/lsst/pipe/tasks/background.py
index beb6f0cde..a15c04bb3 100644
--- a/python/lsst/pipe/tasks/background.py
+++ b/python/lsst/pipe/tasks/background.py
@@ -612,14 +612,14 @@ def __init__(self, config, dims, transform, values=None, numbers=None):
             values.set(0.0)
         else:
             values = values.clone()
-        assert(values.getDimensions() == self.dims)
+        assert values.getDimensions() == self.dims
         self._values = values
         if numbers is None:
             numbers = afwImage.ImageF(self.dims)  # float for dynamic range and convenience
             numbers.set(0.0)
         else:
             numbers = numbers.clone()
-        assert(numbers.getDimensions() == self.dims)
+        assert numbers.getDimensions() == self.dims
         self._numbers = numbers
 
     def __reduce__(self):
diff --git a/python/lsst/pipe/tasks/configurableActions/_configurableActionStructField.py b/python/lsst/pipe/tasks/configurableActions/_configurableActionStructField.py
index 8e7368895..4a371f534 100644
--- a/python/lsst/pipe/tasks/configurableActions/_configurableActionStructField.py
+++ b/python/lsst/pipe/tasks/configurableActions/_configurableActionStructField.py
@@ -161,7 +161,7 @@ def _config(self) -> Config:
         # Config Fields should never outlive their config class instance
         # assert that as such here
         value = self._config_()
-        assert(value is not None)
+        assert value is not None
         return value
 
     @property
diff --git a/python/lsst/pipe/tasks/healSparseMappingProperties.py b/python/lsst/pipe/tasks/healSparseMappingProperties.py
index 25127c054..f60e65b19 100644
--- a/python/lsst/pipe/tasks/healSparseMappingProperties.py
+++ b/python/lsst/pipe/tasks/healSparseMappingProperties.py
@@ -166,13 +166,18 @@ def compute_approx_psf_size_and_shape(ccd_row, ra, dec, nx=20, ny=20, orderx=2,
                                               ("psf_e2", "f8"),
                                               ("psf_area", "f8")])
 
-    cheb_size = ChebyshevBoundedField.fit(lsst.geom.Box2I(bbox), x, y, psf_size, ctrl)
+    # Protect against nans which can come in at the edges and masked regions.
+    good = np.isfinite(psf_size)
+    x = x[good]
+    y = y[good]
+
+    cheb_size = ChebyshevBoundedField.fit(lsst.geom.Box2I(bbox), x, y, psf_size[good], ctrl)
     psf_array["psf_size"] = cheb_size.evaluate(pixel_x, pixel_y)
-    cheb_e1 = ChebyshevBoundedField.fit(lsst.geom.Box2I(bbox), x, y, psf_e1, ctrl)
+    cheb_e1 = ChebyshevBoundedField.fit(lsst.geom.Box2I(bbox), x, y, psf_e1[good], ctrl)
     psf_array["psf_e1"] = cheb_e1.evaluate(pixel_x, pixel_y)
-    cheb_e2 = ChebyshevBoundedField.fit(lsst.geom.Box2I(bbox), x, y, psf_e2, ctrl)
+    cheb_e2 = ChebyshevBoundedField.fit(lsst.geom.Box2I(bbox), x, y, psf_e2[good], ctrl)
     psf_array["psf_e2"] = cheb_e2.evaluate(pixel_x, pixel_y)
-    cheb_area = ChebyshevBoundedField.fit(lsst.geom.Box2I(bbox), x, y, psf_area, ctrl)
+    cheb_area = ChebyshevBoundedField.fit(lsst.geom.Box2I(bbox), x, y, psf_area[good], ctrl)
     psf_array["psf_area"] = cheb_area.evaluate(pixel_x, pixel_y)
 
     return psf_array
diff --git a/tests/test_configurableActions.py b/tests/test_configurableActions.py
index ec87d3068..733c95b9b 100644
--- a/tests/test_configurableActions.py
+++ b/tests/test_configurableActions.py
@@ -36,7 +36,7 @@ def __call__(self):
         return self.var
 
     def validate(self):
-        assert(self.var is not None)
+        assert self.var is not None
 
 
 class ActionTest2(ConfigurableAction):
@@ -46,7 +46,7 @@ def __call__(self):
         return self.var
 
     def validate(self):
-        assert(self.var is not None)
+        assert self.var is not None
 
 
 class ActionTest3(ConfigurableAction):
@@ -56,7 +56,7 @@ def __call__(self):
         return self.var
 
     def validate(self):
-        assert(self.var is not None)
+        assert self.var is not None
 
 
 class ConfigurableActionsTestCase(unittest.TestCase):