Python::Pip fails if $ensure='absent'

[SaschaDoering]

Affected Puppet, Ruby, OS and module versions/distributions

• Puppet: 6.4.2
• Ruby:
• Distribution: Ubuntu
• Module version: 3.0.1

How to reproduce (e.g Puppet code you use)

python::pip { 'PROGRAMM':
  ensure       => 'absent',
  pkgname      => 'PROGRAMM',
  pip_provider => 'pip',
  virtualenv   => '/opt/PROGRAMM',
}

What are you seeing

error during compilation: Evaluation Error: Error while evaluating a Resource Statement, Evaluation Error: Cannot reassign variable '$pip_exec_install'

This occurres in modules/python/manifests/pip.pp in line 224, column 27

What behaviour did you expect instead

A clean run without an error.