Convert string to path using Python 2.7

[tester_V]

Greetings!
I need to find yesterday's modified directories.

but a PC I'm running the code on has Python 2.7 and I cannot use pathlib...
The code I have has a problem (see the error below), I can't get a Path from the string..
"AttributeError: 'str' object has no attribute 'stat'"

I Googled for an answer for about an hour or so but could not find a solution...
Here is the code I got so far:

import os.path
import datetime as dt

tz ='C:\\01'
for dr_name in os.listdir(tz):
    dr_path = os.path.join(tz, dr_name)
    print(type(dr_path)) ## <-- it is alredy a string not Path
    if os.path.isdir(dr_path): 
        print("Directory path name:", dr_path)
        print(type(dr_path))        
        np = os.path.normpath(dr_path) 
        print(type(np))  ## <-- Still string
        yesterday = dt.datetime.now().date() - dt.timedelta(days=1)
        if yesterday == dt.datetime.fromtimestamp(np.stat().st_mtime).date():
            print(f"  Directory modified yesterday -> {np}")

Thank you!