.travis.yml

language: python
python:
 - "3.7"
 - "3.8"
 - "3.9"
install:
  - pip3 install -r requirements.txt
  - pip3 install --upgrade pip
jobs:
  include:
    - name: "Python 3.8.0 on Xenial Linux"
      python: 3.8           # this works for Linux but is ignored on macOS or Windows
    - name: "Python 3.7.4 on macOS"
      os: osx
      osx_image: xcode11.2  # Python 3.7.4 running on macOS 10.14.4
      language: shell       # 'language: python' is an error on Travis CI macOS
    - name: "Python 3.8.0 on Windows"
      os: windows           # Windows 10.0.17134 N/A Build 17134
      language: shell       # 'language: python' is an error on Travis CI Windows
      before_install:
        - choco install python --version 3.8.0
        - python -m pip install --upgrade pip
      env: PATH=/c/Python38:/c/Python38/Scripts:$PATH
script: python3 WPM.py || python WPM.py