diff --git a/100_Numpy_exercises_with_hints_with_solutions.md b/100_Numpy_exercises_with_hints_with_solutions.md
index 59e60fca..cbfc0664 100644
--- a/100_Numpy_exercises_with_hints_with_solutions.md
+++ b/100_Numpy_exercises_with_hints_with_solutions.md
@@ -921,8 +921,8 @@ Z_start = (np.maximum(Z_start,0)).tolist()
 R_stop = np.maximum(R_start, (R_stop - np.maximum(Z_stop-Zs,0))).tolist()
 Z_stop = (np.minimum(Z_stop,Zs)).tolist()
 
-r = [slice(start,stop) for start,stop in zip(R_start,R_stop)]
-z = [slice(start,stop) for start,stop in zip(Z_start,Z_stop)]
+r = tuple(slice(start,stop) for start,stop in zip(R_start,R_stop))
+z = tuple(slice(start,stop) for start,stop in zip(Z_start,Z_stop))
 R[r] = Z[z]
 print(Z)
 print(R)
@@ -1249,4 +1249,4 @@ idx = np.random.randint(0, X.size, (N, X.size))
 means = X[idx].mean(axis=1)
 confint = np.percentile(means, [2.5, 97.5])
 print(confint)
-```
\ No newline at end of file
+```
diff --git a/100_Numpy_exercises_with_solutions.md b/100_Numpy_exercises_with_solutions.md
index 78fd8e95..b5f6e054 100644
--- a/100_Numpy_exercises_with_solutions.md
+++ b/100_Numpy_exercises_with_solutions.md
@@ -921,8 +921,8 @@ Z_start = (np.maximum(Z_start,0)).tolist()
 R_stop = np.maximum(R_start, (R_stop - np.maximum(Z_stop-Zs,0))).tolist()
 Z_stop = (np.minimum(Z_stop,Zs)).tolist()
 
-r = [slice(start,stop) for start,stop in zip(R_start,R_stop)]
-z = [slice(start,stop) for start,stop in zip(Z_start,Z_stop)]
+r = tuple(slice(start,stop) for start,stop in zip(R_start,R_stop))
+z = tuple(slice(start,stop) for start,stop in zip(Z_start,Z_stop))
 R[r] = Z[z]
 print(Z)
 print(R)
@@ -1249,4 +1249,4 @@ idx = np.random.randint(0, X.size, (N, X.size))
 means = X[idx].mean(axis=1)
 confint = np.percentile(means, [2.5, 97.5])
 print(confint)
-```
\ No newline at end of file
+```
diff --git a/source/exercises100.ktx b/source/exercises100.ktx
index 34cd1baa..0ab2f8ca 100644
--- a/source/exercises100.ktx
+++ b/source/exercises100.ktx
@@ -1147,8 +1147,8 @@ Z_start = (np.maximum(Z_start,0)).tolist()
 R_stop = np.maximum(R_start, (R_stop - np.maximum(Z_stop-Zs,0))).tolist()
 Z_stop = (np.minimum(Z_stop,Zs)).tolist()
 
-r = [slice(start,stop) for start,stop in zip(R_start,R_stop)]
-z = [slice(start,stop) for start,stop in zip(Z_start,Z_stop)]
+r = tuple(slice(start,stop) for start,stop in zip(R_start,R_stop))
+z = tuple(slice(start,stop) for start,stop in zip(Z_start,Z_stop))
 R[r] = Z[z]
 print(Z)
 print(R)