pil shwoing ValueError: unknown file extension: when using custom filename itjh os path jion code example

Example: PYTHON INSTALL DIR = os.path.dirname(os.path.dirname(os.__file__)) AttributeError: module 'os' has no attribute '_file_'

# Python program to explain os.path.join() method  
    
# importing os module  
import os 
  
# Path 
path = "/home"
  
# Join various path components  
print(os.path.join(path, "User/Desktop", "file.txt"))