知道为什么会发生此错误吗？我在使用MAC在anaconda3中创建的虚拟环境中。我尝试了先前线程中的几个修复程序，但没有用。
(env)iMac.local:~$pip install --upgrade pip
Requirement already up-to-date: pip in ./anaconda3/envs/CAT/lib/python3.5/site-packages (10.0.1)
distributed 1.21.8 requires msgpack, which is not installed.
(env)iMac.local:~$pip install numpy
Requirement already satisfied: numpy in ./anaconda3/envs/CAT/lib/python3.5/site-packages (1.14.3)
distributed 1.21.8 requires msgpack, which is not installed.
(env)iMac.local:~$pip3 install msgpack-python
Requirement already satisfied: msgpack-python in ./anaconda3/lib/python3.6/site-packages (0.4.8)
(env)iMac.local:~$pip install numpy
Requirement already satisfied: numpy in ./anaconda3/envs/CAT/lib/python3.5/site-packages (1.14.3)
distributed 1.21.8 requires msgpack, which is not installed.
(env)iMac.local:~$pip3 install --only-binary :all: distributed
Requirement already satisfied: distributed in ./anaconda3/lib/python3.6/site-packages (1.19.1)
Requirement already satisfied: tornado>=4.5.1 in ./anaconda3/lib/python3.6/site-packages (from distributed) (4.5.2)
Requirement already satisfied: toolz>=0.7.4 in ./anaconda3/lib/python3.6/site-packages (from distributed) (0.8.2)
Requirement already satisfied: msgpack-python in ./anaconda3/lib/python3.6/site-packages (from distributed) (0.4.8)
Requirement already satisfied: cloudpickle>=0.2.2 in ./anaconda3/lib/python3.6/site-packages (from distributed) (0.4.0)
Requirement already satisfied: dask>=0.14.1 in ./anaconda3/lib/python3.6/site-packages (from distributed) (0.15.3)
Requirement already satisfied: click>=6.6 in ./anaconda3/lib/python3.6/site-packages (from distributed) (6.7)
Requirement already satisfied: six in ./anaconda3/lib/python3.6/site-packages (from distributed) (1.11.0)
Requirement already satisfied: tblib in ./anaconda3/lib/python3.6/site-packages (from distributed) (1.3.2)
Requirement already satisfied: psutil in ./anaconda3/lib/python3.6/site-packages (from distributed) (5.4.0)
Requirement already satisfied: zict>=0.1.3 in ./anaconda3/lib/python3.6/site-packages (from distributed) (0.1.3)
Requirement already satisfied: sortedcontainers in ./anaconda3/lib/python3.6/site-packages (from distributed) (1.5.7)
Requirement already satisfied: heapdict in ./anaconda3/lib/python3.6/site-packages (from zict>=0.1.3->distributed) (1.0.0)
(env)iMac.local:~$pip install numpy
Requirement already satisfied: numpy in ./anaconda3/envs/CAT/lib/python3.5/site-packages (1.14.3)
distributed 1.21.8 requires msgpack, which is not installed.
(env)iMac.local:~$