new_contents: """
  
  """
  
  import logging
  import os
  import sys
  sys.path.insert(0, os.path.abspath(
      os.path.join(os.path.dirname(__file__), os.pardir)
  ))
  
  from modularodm.query.querydialect import DefaultQueryDialect as Q
  
  from website.app import init_app
  from website.models import Node
  
  
  logger = logging.getLogger('root')
  
  app = init_app('website.settings', set_backends=True, routes=True)
  
  
  def copied_from_ancestor(node, attribute):
      parent = getattr(node, attribute)
  
      if (
          parent
          and parent.piwik_site_id is not None
          and parent.piwik_site_id == node.piwik_site_id
      ):
          return True
  
      if parent:
          copied_from_ancestor(parent, attribute)
  
      return False
  
  
  print "=== Registrations ==="
  for node in Node.find(Q('is_registration', 'eq', True)):
      if copied_from_ancestor(node, 'registered_from'):
          node.piwik_site_id = None
          node.save()
          print(node._id)
  
  
  print "=== Forks ==="
  for node in Node.find(Q('is_fork', 'eq', True)):
      if copied_from_ancestor(node, 'forked_from'):
          node.piwik_site_id = None
          node.save()
          print(node._id)
subject: Add migration script for nodes with incorrect piwik_site_id set.