new_contents: from __future__ import absolute_import
  from __future__ import print_function
  from __future__ import division
  
  from ds_queue import Queue
  
  
  def breadth_first_search():
  	pass
  
  
  def main():
  	pass
  
  
  if __name__ == '__main__':
  	main()
  
subject: Add alg_bfs.py