导入zmq时出错

Question

当我导入zmq时出现此错误：

Traceback (most recent call last):
File "<pyshell#5>", line 1, in <module>
import zmq
File "zmq\__init__.py", line 60, in <module>
from zmq.backend import *## Heading ##
File "zmq\backend\__init__.py", line 29, in <module>
_ns = select_backend('zmq.backend.cffi')
File "zmq\backend\select.py", line 31, in select_backend
mod = __import__(name, fromlist=public_api)
File "zmq\backend\cffi\__init__.py", line 12, in <module>
from zmq.backend.cffi import (constants, error, message, context, socket,
File "zmq\backend\cffi\constants.py", line 4, in <module>
from ._cffi import C, c_constant_names
File "zmq\backend\cffi\_cffi.py", line 20, in <module>
from cffi import FFI
ImportError: No module named cffi

如何解决此错误？