diff --git a/jax_galsim/angle.py b/jax_galsim/angle.py
index ed513315..fad56976 100644
--- a/jax_galsim/angle.py
+++ b/jax_galsim/angle.py
@@ -89,7 +89,7 @@ def __repr__(self):
         elif self == arcsec:
             return "galsim.arcsec"
         else:
-            return "galsim.AngleUnit(%r)" % ensure_hashable(self.value)
+            return "galsim.AngleUnit(%r)" % (ensure_hashable(self.value),)
 
     def __eq__(self, other):
         return isinstance(other, AngleUnit) and jnp.array_equal(self.value, other.value)
@@ -222,7 +222,7 @@ def __str__(self):
         return str(ensure_hashable(self._rad)) + " radians"
 
     def __repr__(self):
-        return "galsim.Angle(%r, galsim.radians)" % ensure_hashable(self.rad)
+        return "galsim.Angle(%r, galsim.radians)" % (ensure_hashable(self.rad),)
 
     def __eq__(self, other):
         return isinstance(other, Angle) and jnp.array_equal(self.rad, other.rad)
diff --git a/jax_galsim/box.py b/jax_galsim/box.py
index 95b3d373..6a6ccde9 100644
--- a/jax_galsim/box.py
+++ b/jax_galsim/box.py
@@ -62,7 +62,7 @@ def __str__(self):
             ensure_hashable(self.height),
         )
         if self.flux != 1.0:
-            s += ", flux=%s" % ensure_hashable(self.flux)
+            s += ", flux=%s" % (ensure_hashable(self.flux),)
         s += ")"
         return s
 
@@ -146,9 +146,9 @@ def __repr__(self):
         )
 
     def __str__(self):
-        s = "galsim.Pixel(scale=%s" % ensure_hashable(self.scale)
+        s = "galsim.Pixel(scale=%s" % (ensure_hashable(self.scale),)
         if self.flux != 1.0:
-            s += ", flux=%s" % ensure_hashable(self.flux)
+            s += ", flux=%s" % (ensure_hashable(self.flux),)
         s += ")"
         return s
 
diff --git a/jax_galsim/exponential.py b/jax_galsim/exponential.py
index cbb716ad..1d472544 100644
--- a/jax_galsim/exponential.py
+++ b/jax_galsim/exponential.py
@@ -92,8 +92,8 @@ def __repr__(self):
         )
 
     def __str__(self):
-        s = "galsim.Exponential(scale_radius=%s" % ensure_hashable(self.scale_radius)
-        s += ", flux=%s" % ensure_hashable(self.flux)
+        s = "galsim.Exponential(scale_radius=%s" % (ensure_hashable(self.scale_radius),)
+        s += ", flux=%s" % (ensure_hashable(self.flux),)
         s += ")"
         return s
 
diff --git a/jax_galsim/gaussian.py b/jax_galsim/gaussian.py
index 3b937a11..f9c1616d 100644
--- a/jax_galsim/gaussian.py
+++ b/jax_galsim/gaussian.py
@@ -107,8 +107,8 @@ def __repr__(self):
         )
 
     def __str__(self):
-        s = "galsim.Gaussian(sigma=%s" % ensure_hashable(self.sigma)
-        s += ", flux=%s" % ensure_hashable(self.flux)
+        s = "galsim.Gaussian(sigma=%s" % (ensure_hashable(self.sigma),)
+        s += ", flux=%s" % (ensure_hashable(self.flux),)
         s += ")"
         return s
 
diff --git a/jax_galsim/moffat.py b/jax_galsim/moffat.py
index 22d4e16e..2a9b312b 100644
--- a/jax_galsim/moffat.py
+++ b/jax_galsim/moffat.py
@@ -232,9 +232,9 @@ def __str__(self):
             ensure_hashable(self.scale_radius),
         )
         if self.trunc != 0.0:
-            s += ", trunc=%s" % ensure_hashable(self.trunc)
+            s += ", trunc=%s" % (ensure_hashable(self.trunc),)
         if self.flux != 1.0:
-            s += ", flux=%s" % ensure_hashable(self.flux)
+            s += ", flux=%s" % (ensure_hashable(self.flux),)
         s += ")"
         return s
 
diff --git a/jax_galsim/noise.py b/jax_galsim/noise.py
index 51325ea3..f49ffa50 100644
--- a/jax_galsim/noise.py
+++ b/jax_galsim/noise.py
@@ -171,7 +171,7 @@ def __repr__(self):
         )
 
     def __str__(self):
-        return "galsim.GaussianNoise(sigma=%s)" % (ensure_hashable(self.sigma))
+        return "galsim.GaussianNoise(sigma=%s)" % (ensure_hashable(self.sigma),)
 
     def tree_flatten(self):
         """This function flattens the GaussianNoise into a list of children
diff --git a/jax_galsim/spergel.py b/jax_galsim/spergel.py
index b4b17904..fbc756db 100644
--- a/jax_galsim/spergel.py
+++ b/jax_galsim/spergel.py
@@ -387,7 +387,7 @@ def __str__(self):
             ensure_hashable(self.half_light_radius),
         )
         if self.flux != 1.0:
-            s += ", flux=%s" % ensure_hashable(self.flux)
+            s += ", flux=%s" % (ensure_hashable(self.flux),)
         s += ")"
         return s
 
diff --git a/jax_galsim/transform.py b/jax_galsim/transform.py
index d7d23838..bf9f4f6d 100644
--- a/jax_galsim/transform.py
+++ b/jax_galsim/transform.py
@@ -232,7 +232,7 @@ def __str__(self):
                 ensure_hashable(self._offset.y),
             )
         if self._flux_ratio != 1.0:
-            s += " * %s" % ensure_hashable(self._flux_ratio)
+            s += " * %s" % (ensure_hashable(self._flux_ratio),)
         return s
 
     @property
diff --git a/jax_galsim/wcs.py b/jax_galsim/wcs.py
index fcddf18e..ee18ef33 100644
--- a/jax_galsim/wcs.py
+++ b/jax_galsim/wcs.py
@@ -919,7 +919,7 @@ def __eq__(self, other):
         )
 
     def __repr__(self):
-        return "galsim.PixelScale(%r)" % ensure_hashable(self.scale)
+        return "galsim.PixelScale(%r)" % (ensure_hashable(self.scale),)
 
     def __hash__(self):
         return hash(repr(self))