Pip install Error

Hi

I have followed the below link to setup the development environment for seafile.
https://download.seafile.com/published/seafile-manual/develop/env.md

But i get the following error when i execute, sudo pip install -r requirements.txt
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-9PXfvI/Pillow/