Travis CI Python构建在osx上失败“2.7未安装”

Question

我试图通过特拉维斯CI在Max OSX上构建一些带有包裹的C++代码的Python包。这是我的构建配置：

{
  "os": "osx",
  "env": "PYTHON=3.6 CPP=14 CLANG DEBUG=1",
  "sudo": false,
  "script": [
    "python setup.py install",
    "py.test"
  ],
  "install": [
    "if [ \"$TRAVIS_OS_NAME\" = \"osx\" ]; then\n    if [ \"$PY\" = \"3\" ]; then\n      brew update && brew upgrade python\n    else\n      curl -fsSL https://bootstrap.pypa.io/get-pip.py | $PY_CMD - --user\n    fi\n  fi\nif [[ \"${TRAVIS_OS_NAME}\" == \"osx\" ]]; then\n    export CXX=clang++ CC=clang;\n    # manually install python on osx\n    brew update\n    brew install python3\n    brew reinstall gcc\n    virtualenv venv\n    source venv/bin/activate\n    pip install -r requirements.txt --upgrade\nfi\n",
    "pip install -r requirements.txt --upgrade",
    "python --version"
  ],
  "language": "python",
  "osx_image": "xcode9"
}

我得到以下生成错误：

^{pr2}$

我不知道该怎么办。在