Sample code to try out python's context manager.

cd.py

import os                                                                       
                                                                                
class cd:                                                                       
    def __init__(self, path):                                                   
        print "constructor"                                                     
        self.dest = path                                                        
        self.origin = os.getcwd()                                               
                                                                                
    def __enter__(self):                                                        
        os.chdir(self.dest)                                                     
        print "Entering. Current working directory %s" % os.getcwd()            
                                                                                
    def __exit__(self, exc_type, exc_val, traceback):                           
        if exc_type:                                                            
            print "caught exception"                                            
        os.chdir(self.origin)                                                   
        print "Exiting. Current working directory %s" % os.getcwd()             
                                                                                
                                                                                
if __name__ == '__main__':                                                      
    with cd("testdir"):                                                         
        with open("test", "w") as f:                                            
            f.write("write something\n")