<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def dir_cmd(argv):
 """Print the path for the virtualenv directory"""

    env = parse_envname(argv, lambda : sys.exit('You must provide a valid virtualenv to target'))
    print(workon_home / env)