Add missing imports of sage.rings.abc

Author: Matthias Koeppe

src/sage/functions/special.py

@@ -158,6 +158,7 @@
 #                  https://www.gnu.org/licenses/
 # ****************************************************************************
 
+import sage.rings.abc
 from sage.rings.integer import Integer
 from sage.misc.latex import latex
 from sage.rings.all import ZZ

src/sage/probability/random_variable.py

@@ -15,6 +15,7 @@
 #                  https://www.gnu.org/licenses/
 # ****************************************************************************
 
+import sage.rings.abc
 from sage.structure.parent import Parent
 from sage.functions.log import log
 from sage.functions.all import sqrt