我正在尝试安装dronekit-sitl但是当我运行命令sudo pip dronekit-sitl时，我得到了这个Laptop% sudo -H pip install dronekit-sitl
Requirement already satisfied: dronekit-sitl in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (3.2.0)
Requirement already satisfied: psutil>=3.0 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from dronekit-sitl) (5.4.5)
Requirement already satisfied: dronekit>=2.0.0b6 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from dronekit-sitl) (2.9.1)
Requirement already satisfied: six>=1.10 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from dronekit-sitl) (1.10.0)
Requirement already satisfied: pymavlink==2.0.6 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from dronekit>=2.0.0b6->dronekit-sitl) (2.0.6)
Requirement already satisfied: future==0.15.2 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from dronekit>=2.0.0b6->dronekit-sitl) (0.15.2)
Requirement already satisfied: monotonic==1.2 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from dronekit>=2.0.0b6->dronekit-sitl) (1.2)
serial 0.0.38 has requirement future>=0.16.0, but you'll have future 0.15.2 which is incompatible.
有没有人可以帮我解决这个问题？谢谢。