使用pdfminer解析pdf时忽略编码错误

from pdfminer.pdfparser import PDFParser
from pdfminer.pdfdocument import PDFDocument
from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
from pdfminer.pdfpage import PDFPage
from pdfminer.layout import LAParams
from pdfminer.converter import TextConverter

parser = PDFParser(open('example.pdf', 'rb'))

document = PDFDocument(parser)

rsrcmgr = PDFResourceManager()

laparams = LAParams()
device = TextConverter(rsrcmgr, output, laparams=laparams)

interpreter = PDFPageInterpreter(rsrcmgr, device)

for page in PDFPage.create_pages(document):
    interpreter.process_page(page)

device.close()

device = TextConverter(rsrcmgr, output, laparams=laparams, ignore_bad_chars=True)