Python 2 :: word counting

Scholars,
Your assignment is to produce the top 10 words from decl.txt.  The algorthim is this:
1.
for each word in the file
if the word does not exist in the dictionary
put the word into a dictionary with a value of 1
else
increment the value associated with the word
2.
invert the dictionary
so instead of word->count  mappings, it will contain count->[list,of,words,with,this,count]
3.
sort the [...]