track local variables in a context

gistfile1.py

class LocalsTracker(object):
  def __enter__(self):
    self._locals = locals()
  
  def __exit__(self):
    locals_now = locals()
    # compute diff between locals_now and self.locals...

def foo():
  a = 100
  with LocalsTracker():
    b = 10
    a = 10