Convert a pile of obvious "yes/no" functions to return bool.
diff --git a/Lib/mhlib.py b/Lib/mhlib.py
index 6cf0128..8d0eff1 100644
--- a/Lib/mhlib.py
+++ b/Lib/mhlib.py
@@ -850,8 +850,8 @@
 
     def contains(self, x):
         for lo, hi in self.pairs:
-            if lo <= x <= hi: return 1
-        return 0
+            if lo <= x <= hi: return True
+        return False
 
     def append(self, x):
         for i in range(len(self.pairs)):