new_contents: #!/usr/bin/env python
  # coding:utf8
  from __future__ import print_function
  import sys
  
  try:
  	lineno = int(sys.argv[1])
  	file_path = sys.argv[2]
  except:
  	try:
  		lineno = int(sys.argv[2])
  		file_path = sys.argv[1]
  	except:	
  		print("usage:{0} lineno file_path".format(sys.argv[0]))
  		print("usage:{0} file_path lineno".format(sys.argv[0]))
  		exit(-1)
  
  line_min = min(abs(lineno - 3),lineno)
  line_max = lineno+7
  
  with open(file_path) as f:
  	for n,l in enumerate(f):
  		if n >= line_min and n <= line_max:print("{}:{}".format(n,l),end="")
  
subject: add neighbour.py