使用PyPDF2提取文本时的编码问题

import PyPDF2
import chardet

def extract_text_from_pdf(file_path):
    with open(file_path, 'rb') as file:
        pdf_reader = PyPDF2.PdfFileReader(file)
        text = ''
        for page_num in range(pdf_reader.numPages):
            page = pdf_reader.getPage(page_num)
            text += page.extract_text()
        
        # 检测文本编码
        encoding = chardet.detect(text.encode())['encoding']
        if encoding:
            text = text.decode(encoding)
        
        return text