Trac #31669: make lift_from_homology entirely abstract

sagemath · Apr 23, 2021 · a475f2a · a475f2a
1 parent 57ee0af
commit a475f2a
Showing 1 changed file with 2 additions and 7 deletions.
diff --git a/src/sage/categories/chain_complexes.py b/src/sage/categories/chain_complexes.py
@@ -53,7 +53,7 @@ def super_categories(self):
         return [Modules(base_ring)]
 
     class ParentMethods:
-        @abstract_method(optional=True)
+        @abstract_method
         def homology(self, n=None):
             r"""
             Return the homology of the chain complex.
@@ -114,6 +114,7 @@ def differential(self, *args, **kwargs):
 
             """
 
+        @abstract_method(optional=True)
         def lift_from_homology(self, x):
             r"""
             Lift the homology element ``x`` to the corresponding module.
@@ -123,12 +124,6 @@ def lift_from_homology(self, x):
                 ...
 
             """
-            try:
-                # is homology already a quotient?
-                x.lift()
-            except AttributeError:
-                # if not, this methods needs to be overwritten by parent
-                raise NotImplementedError
 
         def reduce_to_homology(self, x, n=None):
             r"""