convert value under the 'HTTP_CONTENT_LENGTH' key of the META dictionary to an integer of base of value under the 'CONTENT_LENGTH' key of META dictionary, if the key doesnt exists use 0 as the base, substitute the result for content_length.
content_length = int ( META . get ( 'HTTP_CONTENT_LENGTH' , META . get ( 'CONTENT_LENGTH' , 0 ) ) )