pip install ccm gives errror: "ImportError: No module named pathlib"

Hi,

I have python 2.7.18 on RHEL 7.9, pip version 8.1.2, I've already installed pathlib2 via **pip install pathlib2** with success.
However **pip install ccm** gives the following error:

Any help appreciated

Collecting ccm
Using cached https://files.pythonhosted.org/packages/f1/12/091e82033d53b3802e1ead6b16045c5ecfb03374f8586a4ae4673a914c1a/ccm-3.1.5.tar.gz
Collecting pyYaml (from ccm)
Using cached https://files.pythonhosted.org/packages/36/2b/61d51a2c4f25ef062ae3f74576b01638bebad5e045f747ff12643df63844/PyYAML-6.0.tar.gz
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "", line 1, in
File "/tmp/pip-build-I9s1ko/pyYaml/setup.py", line 67, in
import sys, os, os.path, pathlib, platform, shutil, tempfile, warnings
ImportError: No module named pathlib