无法将用户输入与 openpyxl 中的单元格值进行比较

Can't compare user input to cell value in openpyxl

I am trying to ask user input and compare the input to a column in my excel sheet. But I keep getting null and I can't get the compare value.

wb = xl.load_workbook(filename + ".xlsx")
sheet1 = wb.active
wb2 = xl.load_workbook("database.xlsx")
sheet2 = wb2.active
pn = input("Please enter PN: ")
col_B = sheet2['B']
for cell in col_B:
    if cell.value == pn:
        print(cell)
    else:
        print("null")
        break

删除“中断”。否则它将在读取第一个单元格后停止循环。