bpo-29776: Use decorator syntax for properties. (#585)

Lib/lib2to3/pytree.py

@@ -271,7 +271,8 @@ class Node(Base):
         for child in self.children:
             yield from child.pre_order()
 
-    def _prefix_getter(self):
+    @property
+    def prefix(self):
         """
         The whitespace and comments preceding this node in the input.
         """
@@ -279,12 +280,11 @@ class Node(Base):
             return ""
         return self.children[0].prefix
 
-    def _prefix_setter(self, prefix):
+    @prefix.setter
+    def prefix(self, prefix):
         if self.children:
             self.children[0].prefix = prefix
 
-    prefix = property(_prefix_getter, _prefix_setter)
-
     def set_child(self, i, child):
         """
         Equivalent to 'node.children[i] = child'. This method also sets the
@@ -380,18 +380,18 @@ class Leaf(Base):
         """Return a pre-order iterator for the tree."""
         yield self
 
-    def _prefix_getter(self):
+    @property
+    def prefix(self):
         """
         The whitespace and comments preceding this token in the input.
         """
         return self._prefix
 
-    def _prefix_setter(self, prefix):
+    @prefix.setter
+    def prefix(self, prefix):
         self.changed()
         self._prefix = prefix
 
-    prefix = property(_prefix_getter, _prefix_setter)
-
 def convert(gr, raw_node):
     """
     Convert raw node information to a Node or Leaf instance.