bitbarで「ImportError: No module named 'bs4'」となる

bitbarプラグインのディレクトリ：~/Documents/bitbar_plugins

上記ディレクトリで、実行すると正常に動作するのですが、bitbarではImportError: No module named 'bs4'と表示されます。

これはなぜなのでしょうか。

事象の画像

コード

python
1#!/usr/bin/env python
2
3# <bitbar.title>Movie Scheduler</bitbar.title>
4# <bitbar.version>v1.0</bitbar.version>
5# <bitbar.author>hanlio</bitbar.author>
6# <bitbar.author.github>hanlio</bitbar.author.github>
7# <bitbar.dependencies>python</bitbar.dependencies>
8
9# coding: UTF-8
10import urllib2
11import datetime
12from bs4 import BeautifulSoup
13
14# Access URL
15url = "http://movie.zashiki.com/calendar/gw/201812.html"
16
17# url remake html
18html = urllib2.urlopen(url)
19
20# html to BeautifulSoup
21soup = BeautifulSoup(html, "html.parser")
22
23# get title
24title = soup.title.string
25
26print title
27
28# get all tr
29tr = soup.find_all("tr")
30
31# get movie title
32movie_title = []
33
34# today
35dt_now = datetime.datetime.now()
36today = dt_now.strftime('%d')
37
38# find tr
39for tagTR in tr:
40	try:
41		date = tagTR.find("td", "date").string
42		if date:
43			if date.find(today + '(') > 0:
44				movie_title = []
45			movie_title.append(tagTR.find("td", "date").string)
46
47		time = tagTR.find("td", "time").string
48		title = tagTR.find("td", "title").string
49		movie_title.append( time + " | " + title)
50		pass
51
52	except Exception as e:
53		pass
54
55for t in movie_title:
56	print t

バージョン情報

shell
1$ pip --version
2pip 18.1 from /usr/local/lib/python2.7/site-packages/pip (python 2.7)
3
4$pip list
5Package        Version
6-------------- -------
7BeautifulSoup  3.2.1
8beautifulsoup4 4.6.3
9bs4            0.0.1
10pip            18.1
11setuptools     39.1.0
12wheel          0.31.0