Longest common substring for many strings with @dokipen

lcr_test.py

from itertools import izip

def longest_common_substring(string_list):
    def _iter():
        for row in izip(*string_list):
            s = set(row)
            if len(s) == 1:
                yield s.pop()
            else:
                return

    return ''.join(_iter())


if __name__ == '__main__':
    test = [
        'abcdef',
        'abcdefg',
        'abcdefgh',
        'abcdefghi'
        'abcdefghij',
    ]
    print longest_common_substring(test)

Original idea and code came from Eric here: http://stackoverflow.com/questions/18715688/find-common-substring-between-two-strings and @dokipen & I adapted it to accept many strings and to use izip