python - ImportError: _imaging C モジュールがインストールされていませんか? PIL Python3

Question

root@syscomp1:~# cd Pillow-master
root@syscomp1:~/Pillow-master# python3 selftest.py
Traceback (most recent call last):
  File "selftest.py", line 8, in <module>
    from PIL import Image
  File "./PIL/Image.py", line 155, in <module>
    if hasattr(core, 'DEFAULT_STRATEGY'):
  File "./PIL/Image.py", line 39, in __getattr__
    raise ImportError("The _imaging C module is not installed")
ImportError: The _imaging C module is not installed
root@syscomp1:~/Pillow-master#

これは PIL をインストールする前のステップです

sudo apt-get install python-pip python-dev build-essential 
sudo pip install --upgrade pip 
sudo pip install --upgrade virtualenv 
sudo aptitude install python3-setuptools
sudo easy_install3 pip
sudo apt-get install python3-dev
download the Pillow-master.zip
wget https://github.com/python-imaging/Pillow/archive/master.zip
go to downloaded directory and,
sudo unzip master.zip
sudo apt-get install libjpeg62-dev //must install this
sudo apt-get install zlib1g-dev
sudo apt-get install libfreetype6-dev
sudo apt-get install liblcms1-dev
python3 setup.py build_ext -i

The _imaging C module is not installedしかし、なぜエラーですか？