Add repr to Reversal for pretty print

SBR.py

@@ -35,9 +35,12 @@ class Reversal:
     def __lt__(self, other):
         return self.beg < other.beg
 
-    def __str__(self):
+    def __repr__(self):
         return "(" + str(self.beg) + ", " + str(self.end) + ")"
 
+    def __str__(self):
+        return repr(self)
+
 
 # Perform the given reversal on the given permutation
 def reverse(permutation, reversal):