python_syntax_using_enter_exit

gistfile1.txt

class MessageWriter(object):
		def __init__(self, file_name):
			self.file_name = file_name
		 
		def __enter__(self):
			self.file = open(self.file_name, 'w')
			return self.file
	 
		def __exit__(self, *args):
			self.file.close()
	 
with MessageWriter('my_file.txt') as xfile:
  xfile.write('hello world')