ModuleNotFoundError: No module named 'Cython'

[decryp2kanon]

Ubuntu 20.04.2 LTS

when i try build from source

$ sudo make install
python3 setup.py install --root=/
Traceback (most recent call last):
  File "setup.py", line 28, in <module>
    from Cython.Distutils import build_ext
ModuleNotFoundError: No module named 'Cython'
make: *** [Makefile:12: install_library] Error 1

but, already installed cython

$ pip3 install Cython
Requirement already satisfied: Cython in /home/vm/.local/lib/python3.8/site-packages (0.29.22)

$ pip3 install pycocotools
Requirement already satisfied: pycocotools in /home/vm/.local/lib/python3.8/site-packages (2.0.2)
Requirement already satisfied: matplotlib>=2.1.0 in /home/vm/.local/lib/python3.8/site-packages (from pycocotools) (3.4.1)
Requirement already satisfied: setuptools>=18.0 in /usr/lib/python3/dist-packages (from pycocotools) (45.2.0)
Requirement already satisfied: cython>=0.27.3 in /home/vm/.local/lib/python3.8/site-packages (from pycocotools) (0.29.22)
Requirement already satisfied: numpy>=1.16 in /home/vm/.local/lib/python3.8/site-packages (from matplotlib>=2.1.0->pycocotools) (1.20.2)
Requirement already satisfied: cycler>=0.10 in /home/vm/.local/lib/python3.8/site-packages (from matplotlib>=2.1.0->pycocotools) (0.10.0)
Requirement already satisfied: pillow>=6.2.0 in /usr/lib/python3/dist-packages (from matplotlib>=2.1.0->pycocotools) (7.0.0)
Requirement already satisfied: python-dateutil>=2.7 in /usr/lib/python3/dist-packages (from matplotlib>=2.1.0->pycocotools) (2.7.3)
Requirement already satisfied: kiwisolver>=1.0.1 in /home/vm/.local/lib/python3.8/site-packages (from matplotlib>=2.1.0->pycocotools) (1.3.1)
Requirement already satisfied: pyparsing>=2.2.1 in /home/vm/.local/lib/python3.8/site-packages (from matplotlib>=2.1.0->pycocotools) (2.4.7)
Requirement already satisfied: six in /usr/lib/python3/dist-packages (from cycler>=0.10->matplotlib>=2.1.0->pycocotools) (1.14.0)

whats the problem?

[decryp2kanon]

solved.

sudo python3 setup.py install