src/sage/geometry/abc.pyx: Add doctests

sagemath · Oct 18, 2021 · ceff8dc · ceff8dc
1 parent 18aa26f
commit ceff8dc
Showing 1 changed file with 18 additions and 0 deletions.
diff --git a/src/sage/geometry/abc.pyx b/src/sage/geometry/abc.pyx
@@ -22,6 +22,24 @@ class ConvexRationalPolyhedralCone:
 class Polyhedron:
     r"""
     Abstract base class for :class:`~sage.geometry.polyhedron.base.Polyhedron_base`
+
+    This class is defined for the purpose of ``isinstance`` tests.  It should not be
+    instantiated.
+
+    EXAMPLES::
+
+        sage: import sage.geometry.abc
+        sage: P = polytopes.cube()                                # optional - sage.geometry.polyhedron
+        sage: isinstance(P, sage.geometry.abc.Polyhedron)         # optional - sage.geometry.polyhedron
+        True
+
+    By design, there is a unique direct subclass of :class:`~sage.geometry.polyhedron.base.Polyhedron_base`::
+
+        sage: sage.geometry.abc.Polyhedron.__subclasses__()       # optional - sage.geometry.polyhedron
+        [<class 'sage.geometry.polyhedron.base.Polyhedron_base'>]
+
+        sage: len(sage.geometry.abc.Polyhedron.__subclasses__()) <= 1
+        True
     """
 
     pass