pip install failed

[lunasdejavu]

the error message for 'twitterscraper -h':
Traceback (most recent call last):
File "/usr/local/bin/twitterscraper", line 5, in
from twitterscraper.main import main
File "/usr/local/lib/python3.7/dist-packages/twitterscraper/init.py", line 13, in
from twitterscraper.query import query_tweets
File "/usr/local/lib/python3.7/dist-packages/twitterscraper/query.py", line 76, in
proxies = get_proxies()
File "/usr/local/lib/python3.7/dist-packages/twitterscraper/query.py", line 47, in get_proxies
soup = BeautifulSoup(response.text, 'lxml')
File "/usr/lib/python3/dist-packages/bs4/init.py", line 165, in init
% ",".join(features))
bs4.FeatureNotFound: Couldn't find a tree builder with the features you requested: lxml. Do you need to install a parser library?

python version is 3.7.5