零基础入门学习python的第31课后题，求大佬告诉我为什么报这个错误

1365156784

import pickle

count=1
dialog1=['oj']
dialog2=['bk']
boy_file_name='小甲鱼_1.txt'
girl_file_name='小客服_1.txt'
tell=open('record.txt')
for each_line in tell:
    if each_line[:6]!= '======':
        if each_line.split(':')[0]=='小甲鱼':
            
            dialog1.append(each_line.split(':')[1])
        if each_line.split(':')[0]=='小客服':
            
            dialog2.append(each_line.split(':')[1])
    else:
        f=open(boy_file_name,'wb')
        m=open(girl_file_name,'wb')
        pickle.dump(dialog1,boy_file_name)
        pickle.dump(dialog2,girl_file_name)
        f.close()
        m.close()
        count+=1
        boy_file_name='boy_'+str(count)+'.txt'
        girl_file_name='girl_'+str(count)+'.txt'
        dialog1=[]
        dialog2=[]
        
tell.close()


Traceback (most recent call last):
  File "C:\Users\86187\Desktop\dialog.py", line 20, in <module>
    pickle.dump(dialog1,boy_file_name)
TypeError: file must have a 'write' attribute