코드 실행 에러

[DanielK720]

안녕하세요, 파이썬 시작한지 얼마 안된 초보입니다. 다름이 아니라 아나콘다3에다가 pip install dart-fss를 통해서 dart-fss를 다운받고, documentation QuickStarts에 있는 코드를 실행해보았는데, 에러가 뜨더라고요. 무슨 문제가 있는걸까요?
import dart_fss as dart
코드:
api_key='cb5e222f0c3ef6f6925c0014f2992d9e15e1ca77'
dart.set_api_key(api_key=api_key)

corp_list = dart.get_corp_list()

samsung = corp_list.find_by_corp_name('삼성전자', exactly=True)[0]

fs = samsung.extract_fs(bgn_de='20120101')

fs.save()

실행결과:
C:\Users\user\anaconda3\python.exe C:/Users/user/Desktop/python_class/pythonProject/main.py
Traceback (most recent call last):
File "C:\Users\user\Desktop\python_class\pythonProject\main.py", line 1, in
import dart_fss as dart
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss_init_.py", line 2, in
from dart_fss import api, auth, corp, errors, filings, fs, utils, xbrl
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss\corp_init_.py", line 2, in
from dart_fss.corp.corp import Corp
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss\corp\corp.py", line 8, in
from dart_fss.filings import search as se
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss\filings_init_.py", line 2, in
from dart_fss.filings.search import search
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss\filings\search.py", line 4, in
from dart_fss.filings.search_result import SearchResults
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss\filings\search_result.py", line 5, in
from dart_fss.filings.reports import Report
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss\filings\reports.py", line 11, in
from dart_fss.xbrl import get_xbrl_from_file
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss\xbrl_init_.py", line 2, in
from .xbrl import get_xbrl_from_file
File "C:\Users\user\anaconda3\lib\site-packages\dart_fss\xbrl\xbrl.py", line 5, in
from arelle import Cntlr
File "C:\Users\user\anaconda3\lib\site-packages\arelle\Cntlr.py", line 13, in
from arelle import ModelManager
File "C:\Users\user\anaconda3\lib\site-packages\arelle\ModelManager.py", line 8, in
from arelle import ModelXbrl, Validate, DisclosureSystem, PackageManager
File "C:\Users\user\anaconda3\lib\site-packages\arelle\ModelXbrl.py", line 11, in
from arelle import UrlUtil, XmlUtil, ModelValue, XbrlConst, XmlValidate
File "C:\Users\user\anaconda3\lib\site-packages\arelle\XmlUtil.py", line 12, in
from lxml import etree
ImportError: DLL load failed while importing etree: 지정된 프로시저를 찾을 수 없습니다.

Process finished with exit code 1