Convert string to path using Python 2.7

[tester_V]

I made changes to the code, I think I'm very close but failing to compare 2(two) time stamps.
yesterday var is formated as YYYY-MM-DD
and the ts var as YYYY-MM-DD HH:MM:SS.milliseconds

for dr_name in os.listdir(tz):
    dr_path = os.path.join(tz, dr_name)
    if os.path.isdir(dr_path): 
        print("Directory path name:", dr_path)       
        yesterday = dt.datetime.now().date() - dt.timedelta(days=1)
        ts = datetime.datetime.fromtimestamp(os.path.getmtime(dr_path))
        print(f" File T_stamp > {ts}")
        if datetime.datetime.fromtimestamp(os.path.getmtime(dr_path)) == yesterday:
            print(f" Yesterday file -> {dr_path}")