Why does `pip` throw `ModuleNotFoundError` even though `setuptools` appears to be installed?

On an EC2 instance, I am attempting to install a Python package using pip, but receive an exception that states

: No module named 'setuptools'

. For context, the command I run is

pip install --user mlflow

I attempt to resolve the issue my installing setuptools with the following command:

yum install python36-setuptools

. Yet, the message returned indicates that setuptools is already installed:

Package python36-setuptools-36.2.7-1.33.amzn1.noarch already installed and latest version
Nothing to do

Please advise. **UPDATE**: After switching the EC2 instance from Amazon Linux AMI 2018.03.0 to Amazon Linux 2 AMI I was able to successfully install mlflow using pip. The question still remains - why was I able to successfully install using Amazon Linux 2 AMI but not Amazon Linux AMI 2018.03.0?