打印的内容显示正常，而在输出的文件中内容却是重复的并且显示的是列表最后一个元素？

# -*- coding: utf-8 -*-
# 存放桌面路径
path = "C:\\Users\\hkcmd\\Desktop\\"

bp = [{"Link":"Net1@a","Name":"aa","Desc":"AA","SN":"49","Vl":"false","Fn":"3","Ad":"1200","RC":"1","VT":"4","KV":"1","BV":"0","ST":"50","PY":"0","Bl":"0"}]

A = [
    [28, 'a', 'A', 1217],
    [29, 'b', 'B', 1219],
    [30, 'c', 'C', 2201],
    [31, 'd', 'D', 2202],
    [32, 'e', 'E', 4203],
    [33, 'f', 'F', 4220]     
]


# 写入数据到指定文件
def WriteData(name, data):
    pfile = open(path + name,'a')
    pfile.write(data + "\n")
    pfile.close()

# 返回数据坐标
def xx(x):
    return x - (x // 1000 - 1) * 1000

def X():
    bm = []
    for i in range(5):
        addr = xx(A[i][-1])
        if addr >= 1200 and addr < 1300:
            bp[0]['Name'] = A[i][1]
            bp[0]['Desc'] = A[i][2]            
            bp[0]['SN'] = str(A[i][0])            
            bp[0]['Link'] = 'Net1@' + A[i][1]
            bp[0]['Ad'] = str(A[i][-1])
            bm.append(bp[0])
            print(bp[0])
    return bm
   
WriteData("uuu.csv","\n".join("%s" %x for x in X()))