求救！Python的EOF问题

zchar

初学Python，写了个很菜的程序，实在不知道哪儿出毛病了，请高手看看，谢谢！


#Filename:mab_ver1.py

import cPickle as cp
import sys

mylist='myinfolist.data'
maindict={}
mainlist=[]

class Person:
   def __init__(self,n,a,p):
        self.name=n
        self.addr=a
        self.phon=p
   def writeData(self):   
        f=file(mylist,'w')
        f.close()
        f=file(mylist)
        mainlist=cp.load(f)
        for k,v in mainlist:
            maindict[k]=v
        maindict[self.name]="%s %s"%(self.addr,self.phon)
        mainlist=maindict.items()
        f=file(mylist,'w')
        cp.dump(mainlist,f)
        f.close()

if len(sys.argv)<2:
    print 'No acion specified.'
    sys.exit()

if sys.argv[1].startswith('add'):
    name=raw_input('Please Enter the Name:')
    addr=raw_input('Please Enter the Address:')
    phon=raw_input('Please Enter the Phone Number:')
    p=Person(name,addr,phon)
    p.writeData()
    sys.exit()

if sys.argv[1].startswith('del'):
        name=raw_input('Please Enter the Name You Want to Delete:')
        f=file(mylist,'w')
        mainlist=cp.load(f)
        for k,v in mainlist:
            maindict[k]=v
        if name in mainlist:
            del maindict[name]
        else:
            print "%s doesn't exist" %name
        mainlist=maindict.items()
        cp.dump(mainlist,f)
        f.close()
        sys.exit()

每次运行时都会报错：
Traceback (most recent call last):
  File "C:\Python23\Lib\site-packages\Pythonwin\pywin\framework\scriptutils.py", line 310, in RunScript
    exec codeObject in __main__.__dict__
  File "C:\Documents and Settings\zchar\My Documents\mab_ver1.py", line 37, in ?
    p=Person(name,addr,phon)
  File "C:\Documents and Settings\zchar\My Documents\mab_ver1.py", line 19, in writeData
    mainlist=cp.load(f)
EOFError