Import cElementTree failed with pyenv and python 2.7.12

I have tried to import cElementTree, but failed.

Python 2.7.12 (default, Jul 19 2018, 15:12:44)
[GCC 4.8.4] on linux2
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>>> import xml.etree.cElementTree
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/tomcat/.pyenv/versions/2.7.12/lib/python2.7/xml/etree/cElementTree.py", line 3, in <module>
    from _elementtree import *
ImportError: No module named _elementtree

It looks _elementtree module (C lang module ?) doesn't exist in pyenv environment. What should I do ?

Solution

I've re-install python 2.7.12 from pyenv. The problem is resolved.