File "2.py", line 10, in <module>
    for i in xrange((line)-step))
TypeError: unsupported operand type(s) for -: 'list' and 'int'

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import csv

data = csv.reader(open('Input.csv', 'r'), delimiter=',', quotechar='|') 
for line in data:
    step = 28
    it = (line[i:i+step] 
    for i in xrange((line)-step))
    print it

import csv

data = csv.reader(open('Input.csv', 'r'), delimiter=',', quotechar='|') 
for line in data:
    print line

[olga ~/python_file/generator]-% python 2.py
['abcdefghijklmnopqrstuvwxyzhdfjkdhfreiufrejkhgjsdgfksfgkljetrhtruihtkjhgosigjlkdhrskjdge']

data = open('Input.csv', 'r')
for line in data:
   print line

step = 28
it = (line[i:i+step] for i in xrange((line)-step))

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import csv
data = open('Input.csv', 'r')
for string in data.readlines():
    step = 28
    it = (string[i:i+step] for i in xrange(len(string)-step))
    for row in it:   
        print row

[olga ~/python_file/generator]-% python 4.py
abcdefghijklmnopqrstuvwxyzhd
bcdefghijklmnopqrstuvwxyzhdf
cdefghijklmnopqrstuvwxyzhdfj
defghijklmnopqrstuvwxyzhdfjk
efghijklmnopqrstuvwxyzhdfjkd
......................................
kljetrhtruihtkjhgosigjlkdhrs
ljetrhtruihtkjhgosigjlkdhrsk
jetrhtruihtkjhgosigjlkdhrskj
etrhtruihtkjhgosigjlkdhrskjd
trhtruihtkjhgosigjlkdhrskjdg