#!/usr/bin/env python
 
 import argparse
 
 import dateparser
 
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Convert date from human format")
     parser.add_argument(
         "when", type=dateparser.parse, help="date specification, e.g. 'yesterday'"
     )
     args = parser.parse_args()
     print(args.when.strftime("%Y_%m_%d"))