setter for vol name

directory.py

@@ -53,6 +53,10 @@ class AbstractFolder(collections.MutableMapping):
     def __len__(self):
         return len(self._maindict)
 
+    def __repr__(self):
+        the_dict = {self._prefdict[k]: v for (k, v) in self._maindict.items()}
+        return repr(the_dict)
+
     def iter_paths(self):
         for name, child in self.items():
             print(name, child)

main.py

@@ -103,7 +103,16 @@ class Volume(_directory.AbstractFolder):
         self.bootblocks = bytes(1024)       # optional; for booting HFS volumes
         self.crdate = 0                     # date and time of volume creation
         self.lsmod = 0                      # date and time of last modification
-        self.name = b'Untitled'
+        self._name = b'Untitled'
+
+    @property
+    def name(self):
+        return self._name
+    @name.setter
+    def name(self, value):
+        if len(value) > 27:
+            raise ValueError('Max volume name length = 27')
+        self._name = value
 
     def read(self, from_volume):
         self._dirtree = {}