default category based on posets

Co-authored-by: Travis Scrimshaw <[email protected]>

Author: fchapoton

src/sage/combinat/posets/lattices.py

@@ -734,9 +734,8 @@ def LatticePoset(data=None, *args, **options):
                 error.x = P._vertex_to_element(error.x)
                 error.y = P._vertex_to_element(error.y)
                 raise
-    cat = options.get('category', None)
-    if cat is None:
-        cat = FiniteLatticePosets()
+    cat = Posets().or_subcategory(options.get('category', None))
+    cat = cat & FiniteLatticePosets()
     return FiniteLatticePoset(P, category=cat, facade=P._is_facade)