Failed to change folder path in python but I do not know why

Question

I want to open the font in folder 1 and folder 2. I wrote openOTF.py to open them.

Desktop 
├── openOTF.py
├── 1
│   ├── CMBSY7.otf
│   ├── CMBSY8.otf
│   └── CMBSY9.otf
├── 2
│   ├── CMCSC8.otf
│   └── CMCSC9.otf

this is openOTF.py

import fontforge as ff
import os

folders = ["1/", "2/"]

for folder in folders:
    os.chdir(folder)
    print(os.getcwd())
    files = os.listdir("./")
    for font in files:
        print(font)
        f = ff.open(font)
        print(f.path)
    os.chdir("../")

but this is the output of python open-otf.py , which cannot find CMCSC8.otf in folder 2 , in fact it want to search /home/firestar/Desktop/1/CMCSC8.otf :

/home/firestar/Desktop/1
CMBSY9.otf
/home/firestar/Desktop/1/CMBSY9.otf
CMBSY8.otf
/home/firestar/Desktop/1/CMBSY8.otf
CMBSY7.otf
/home/firestar/Desktop/1/CMBSY7.otf
/home/firestar/Desktop/2
CMCSC8.otf
The requested file, CMCSC8.otf, does not exist
Traceback (most recent call last):
  File "/home/firestar/Desktop/open-otf.py", line 12, in <module>
    f = ff.open(font)
OSError: Open failed

it seems that os.chdir("../") changed the path to folder 2 but fontforge did not change the path (still in folder 1 ).

Answer 1

import fontforge as ff
import glob

files = glob.glob('*/*.otf')
print(files)

for font in files:
    f = ff.open(font)
    print(f.path)

I think glob is the simplest solution