Error when installing python3 packages in Virtualenv using pip

Question

i am trying install pytrend (included some packages eg: numpy , pandas, ... ) in my virtual environment, after activating the venv and running

pip install pytrends

the command line troughs this error :

> Command /root/environments/my_env/bin/python3 -c "import setuptools,
> tokenize;__file__='/root/environments/my_env/build/lxml/setup.py';exec(compile(getattr(tokenize,
> 'open', open)(__file__).read().replace('\r\n', '\n'), __file__,
> 'exec'))" install --record /tmp/pip-ibvjaren-record/install-record.txt
> --single-version-externally-managed --compile --install-headers /root/environments/my_env/include/site/python3.4 failed with error
> code 1 in /root/environments/my_env/build/lxml Storing debug log for
> failure in /root/.pip/pip.log

i am using python3.4 and ubuntu 14.04, did I missed something?

Edit 1: here is /root/.pip/pip.log contents

> Cleaning up...   Removing temporary dir
> /root/environments/my_env/build... Command
> /root/environments/my_env/bin/python3 -c "import setuptools,
> tokenize;__file__='/root/environments/my_env/build/lxml/setup.py';exec(compile(getattr($
> Exception information: Traceback (most recent call last):   File
> "/root/environments/my_env/lib/python3.4/site-packages/pip/basecommand.py",
> line 122, in main
>     status = self.run(options, args)   File "/root/environments/my_env/lib/python3.4/site-packages/pip/commands/install.py",
> line 283, in run
>     requirement_set.install(install_options, global_options, root=options.root_path)   File
> "/root/environments/my_env/lib/python3.4/site-packages/pip/req.py",
> line 1436, in install
>     requirement.install(install_options, global_options, *args, **kwargs)   File "/root/environments/my_env/lib/python3.4/site-packages/pip/req.py",
> line 707, in install
>     cwd=self.source_dir, filter_stdout=self._filter_install, show_stdout=False)   File
> "/root/environments/my_env/lib/python3.4/site-packages/pip/util.py",
> line 715, in call_subprocess
>     % (command_desc, proc.returncode, cwd)) pip.exceptions.InstallationError: Command
> /root/environments/my_env/bin/python3 -c "import setuptools,
> tokenize;__file__='/root/environments/my_env/build/lx$

PS : I rebuilt the Vps OS, but this issue not solved yet.