Python CSV module __getitem__ issue

# test.py
import csv
import collections

index = collections.defaultdict(list)
file1= open( "someFile.csv", "rb" )
rdr= csv.DictReader( file1 )
for row in rdr:
    index[rdr['MPID']].append( row )
file1.close()

file2= open( "anotherFile.csv", "rb" )
rdr= csv.DictReader( file2 )
for row in rdr:
    print row, index[row['MPID']]
file2.close()

# someFile.csv
MPID,Title,Description,Model,Category ID,Category Description,Subcategory ID,Subcategory Description,Manufacturer ID,Manufacturer Description,URL,Manufacturer (Brand) URL,Image URL,AR Price,Price,Ship Price,Stock,Condition
4,"Foo","Bar","FooBar",13,"Thirteen",4,"Four",7,"Seven","http://foobar.com/foobar",,"$4.00","$5.00","$10.00","$5.00",4,"New"

# anotherFile.csv
Regular Price,Sale Price,Manufacturer Name,Model Number,Retailer Category,Buy URL,Product Name,Availability,Shipping Cost,Condition,MPID,Image URL,UPC,Description
"$5.00","$4.00","FooBar","M-18-45","Soap","htpp://foobar.com/buy?M-18-45","Restful SOAP",4,"$5.00","New",4,,"7777-999-3","Beauty Soap"

# python2.6 test.py
# Traceback (most recent call last):
#   File "test.py", line 8, in <module>
#     index[rdr['MPID']].append( row )
# AttributeError: DictReader instance has no attribute '__getitem__'