面对"缺少XCode依赖项：Python模块"六"，即使安装了六个
Pip Already installed
pip install six
Requirement already satisfied: six in /usr/local/lib/python2.7/site-packages
(1.11.0)
但仍然颤动医生要求安装pip
Shivas-MacBook-Pro:Flutter shivapokala$ flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, v0.5.1, on Mac OS X 10.13.5 17F77, locale en-US)
[✓] Android toolchain - develop for Android devices (Android SDK 27.0.0)
[!] iOS toolchain - develop for iOS devices (Xcode 9.4.1)
✗ Missing Xcode dependency: Python module "six".
Install via 'pip install six' or 'sudo easy_install six'.
[✓] Android Studio (version 3.1)
[!] Connected devices
! No devices available
! Doctor found issues in 2 categories.
根据这个，尝试：
python2.x -m pip install six
或：
brew reinstall python@2
pip install six