Do not use block # optional until #35749 is merged

Author: Matthias Koeppe

src/sage/combinat/designs/block_design.py

@@ -934,13 +934,12 @@ def WittDesign(n):
 
     EXAMPLES::
 
-        sage: # optional - gap_packages (design package)
-        sage: BD = designs.WittDesign(9)
-        sage: BD.is_t_design(return_parameters=True)
+        sage: BD = designs.WittDesign(9)             # optional - gap_packages (design package)
+        sage: BD.is_t_design(return_parameters=True) # optional - gap_packages (design package)
         (True, (2, 9, 3, 1))
-        sage: BD
+        sage: BD                             # optional - gap_packages (design package)
         Incidence structure with 9 points and 12 blocks
-        sage: print(BD)
+        sage: print(BD)                      # optional - gap_packages (design package)
         Incidence structure with 9 points and 12 blocks
     """
     libgap.load_package("design")

src/sage/combinat/designs/incidence_structures.py

@@ -1538,14 +1538,13 @@ def is_t_design(self, t=None, v=None, k=None, l=None, return_parameters=False):
 
         Some examples of Witt designs that need the gap database::
 
-            sage: # optional - gap_packages
-            sage: BD = designs.WittDesign(9)
-            sage: BD.is_t_design(2,9,3,1)
+            sage: BD = designs.WittDesign(9)         # optional - gap_packages
+            sage: BD.is_t_design(2,9,3,1)            # optional - gap_packages
             True
-            sage: W12 = designs.WittDesign(12)
-            sage: W12.is_t_design(5,12,6,1)
+            sage: W12 = designs.WittDesign(12)       # optional - gap_packages
+            sage: W12.is_t_design(5,12,6,1)          # optional - gap_packages
             True
-            sage: W12.is_t_design(4)
+            sage: W12.is_t_design(4)                 # optional - gap_packages
             True
 
         Further examples::