Example of refactoring using rope library.

tools/telemetry/third_party/rope/rope/base/astutils.py

+from rope.base import ast
+
+
+def get_name_levels(node):
+    """Return a list of ``(name, level)`` tuples for assigned names
+
+    The `level` is `None` for simple assignments and is a list of
+    numbers for tuple assignments for example in::
+
+      a, (b, c) = x
+
+    The levels for for `a` is ``[0]``, for `b` is ``[1, 0]`` and for
+    `c` is ``[1, 1]``.
+
+    """
+    visitor = _NodeNameCollector()
+    ast.walk(node, visitor)
+    return visitor.names
+
+
+class _NodeNameCollector(object):
+
+    def __init__(self, levels=None):
+        self.names = []
+        self.levels = levels
+        self.index = 0
+
+    def _add_node(self, node):
+        new_levels = []
+        if self.levels is not None:
+            new_levels = list(self.levels)
+            new_levels.append(self.index)
+        self.index += 1
+        self._added(node, new_levels)
+
+    def _added(self, node, levels):
+        if hasattr(node, 'id'):
+            self.names.append((node.id, levels))
+
+    def _Name(self, node):
+        self._add_node(node)
+
+    def _Tuple(self, node):
+        new_levels = []
+        if self.levels is not None:
+            new_levels = list(self.levels)
+            new_levels.append(self.index)
+        self.index += 1
+        visitor = _NodeNameCollector(new_levels)
+        for child in ast.get_child_nodes(node):
+            ast.walk(child, visitor)
+        self.names.extend(visitor.names)
+
+    def _Subscript(self, node):
+        self._add_node(node)
+
+    def _Attribute(self, node):
+        self._add_node(node)
+
+    def _Slice(self, node):
+        self._add_node(node)