【报错】Python中expected an indented block

IndentationError: expected an indented block
Python严格地要求代码缩进，缩进的代码块相对于上一级是从属关系。用if语句举个例子：
if a==2: print ‘hello world’if语句的条件为真时会执行print语句，print语句是if语句的从属代码块，代表从属关系，print语句之前有4个空格。如果if语句没有任何从属的代码块就会报错expected an indented block。与if语句类似的，必须包含从属代码块的还有while、for、try-except等。

for i in range(1,len(data)):
    if data['6点非预约在线时长(分钟)'][i]>0&data['7点非预约在线时长(分钟)'][i]>0&data['8点非预约在线时长(分钟)'][i]>0:
        data['早高峰在线情况'][i] = '早高峰在线司机'
    elif data['6点非预约在线时长(分钟)'][i]=0&data['7点非预约在线时长(分钟)'][i]>0&data['8点非预约在线时长(分钟)'][i]>0:
        data['早高峰在线情况'][i] = '7点在线司机'
    elif data['6点非预约在线时长(分钟)'][i]=0&data['7点非预约在线时长(分钟)'][i]=0&data['8点非预约在线时长(分钟)'][i]>0:
        data['早高峰在线情况'][i] = '8点在线司机'
    else:
        data['早高峰在线情况'][i] = '待定司机'