src/sage/manifolds/differentiable/examples/real_line.py: Use declare_…

…subset
sagemath · May 2, 2021 · 0cc9eb8 · 0cc9eb8
1 parent a6a7f02
commit 0cc9eb8
Showing 1 changed file with 1 addition and 3 deletions.
diff --git a/src/sage/manifolds/differentiable/examples/real_line.py b/src/sage/manifolds/differentiable/examples/real_line.py
@@ -376,9 +376,7 @@ def __init__(self, lower, upper, ambient_interval=None,
             if upper > ambient_interval.upper_bound():
                 raise ValueError("the upper bound is larger than that of "
                                  + "the containing interval")
-            self._supersets.update(ambient_interval._supersets)
-            for sd in ambient_interval._supersets:
-                sd._subsets.add(self)
+            self.declare_subset(ambient_interval)
             ambient_interval._top_subsets.add(self)
             t = ambient_interval.canonical_coordinate()
         if lower != minus_infinity: