Pydub library has an error with version check

I am just curious why only this library has an error of version check.

Below is the code.

import pydub
print('Pydub version: ', pydub.__version__)

I got the error as below.

AttributeError: module 'pydub' has no attribute '__version__'

Other libraries can print their versions.

I could check the version(0.25.1) of 'pydub' by just installing it in prompt as below.

pip install pydub

Are there anyone who know the reason of an error of version check for 'Pydub'?

Alternatively you can get package version from the subprocess - use something like this:

import subprocess
import re

completed = subprocess.run(["pip", "show", "pydub"], stdout=subprocess.PIPE, encoding="utf-8")
text = completed.stdout

res = re.search("Version: ([0-9]*\.[0-9]*\.[0-9]*)", text)
version = res.group(1)

Or alternatively call the pip from the python:

from pip._internal.commands import show

tt= show.search_packages_info(['pydub'])

for pkg in tt:
    print (pkg.name)
    print (pkg.metadata_version)
    print (pkg.version)