docs: def unshare_network(network_id, usernames,**kwargs):
      """
          Un-Share a network with a list of users, identified by their usernames.
      """
  
      user_id = kwargs.get('user_id')
      net_i = _get_network(network_id)
      net_i.check_share_permission(user_id)
  
      for username in usernames:
          user_i = _get_user(username)
          #Set the owner ship on the network itself
  
      net_i.unset_owner(user_i.id, write=write, share=share)
      db.DBSession.flush()