如何对两列求和并将其与通过熊猫进行比较？

Question

第一次在Pandas上工作，我正在尝试使用CSV文件。

1) The CSV file has 4 columns, namely `Employee Name,Gross_Salary,Deduction,Net_Salary`
2) My motive is to find the difference between  "Gross_Salary" and "Deduction", and compare it to "Net_Salary". 
3) If the results matches, then "pass", or "fail".

因此，据我所知，我编写了以下代码，但我认为它需要修改，因为它无法正常工作。下面是示例程序。

import pandas as pd

# Reading the CSV file

df = pd.read_csv(r'xl1.csv')

# Summation pf the two columns and giving results

sum1 = df['Gross_Salary'].sum()
sum2 = df['Deduction'].sum()
diff = sum1 - sum2

if diff == df['Net_salary']:
    print("pass")

else:
    print("Fail")

执行它时，出现错误：KeyError: 'Net_salary'

有帮助吗？

谢谢