在python中使用writerow附加到我的csv

我有一张excel表格,只有一列,标题是Name,下面的行是Jerry。我要做的就是用python加上标题:a g e,然后在下面加一行,比如14。

我该怎么做?

with open('simpleexcel.csv', 'r') as f_input:  # Declared variable f_input to open and read the input file
    input_reader = csv.reader(f_input)  # this will iterate ober lines from input file

    with open('Outputfile.csv', "w", newline='') as f_output:  # opens a file for qwriting in this case outputfile
        line_writer = csv.writer(f_output) #If csvfile is a file object, it should be opened with newline=''
        for line in input_reader: #prints every row
            line_writer.writerow(line+['14'])

相反,我得到14分和14分,我不知道怎么得到另一个头球

我首先要做的是

Name 
Jerry

Name   Age 
Jerry  14 

相反,我得到:

Name   14
Jerry  14 

我怎样才能修改上面的代码?