Game of Life Kata (https://github.com/garora/TDD-Katas#game-of-life-)

life.py

import time

def next_generation(input):
    mygrid = Grid(input)
    mygrid.pretty_print()
    nex_gen_grid = mygrid._next_generation()
    return nex_gen_grid.dump()


class Grid:
    def __init__(self, input):
        self.rows = input.split('\n')[1:]

    @staticmethod
    def from_rows(rows):
        new_grid = Grid('')
        new_grid.rows = rows
        return new_grid

    def _next_generation(self):
        g = []
        for i, row in enumerate(self.rows):
            new_grid = ''
            for j, cell in enumerate(row):
                new_grid += self.find_cell_results(i, j)
            g.append(new_grid)
        return Grid.from_rows(g)

    def find_cell_results(self, i, j):
        list_of_coords = self.get_neighbour_coords(i ,j)
        count = sum([self.check_for_life(coord) for coord in list_of_coords])
        if count in [2, 3] and self.check_for_life((i ,j)):
            return '*'
        elif count == 3 and not self.check_for_life((i, j)):
            return '*'
        else:
            return '.'

    def get_neighbour_coords(self, i, j):
	all_directions = [
        (1, 1), 
        (-1, -1), 
        (1, -1), 
        (-1, 1), 
        (1, 0), 
        (-1, 0), 
        (0, 1), 
        (0, -1)
    ]
	all_neighbour_coords = map (lambda (x, y): (i + x, j + y) , all_directions)
	return all_neighbour_coords

    def check_for_life(self, coord):
	try:
		if coord[0] < 0 or coord[1] < 0:
	            return 0
		if self.rows[coord[0]][coord[1]] == '*':
		    return 1
		else:
		    return 0
	except IndexError:
		return 0
        
    def dump(self):
        size = str(len(self.rows[0])) + ' ' + str(len(self.rows))
        gridstr = '\n'.join(self.rows)
        return "\n".join([size, gridstr])

    def pretty_print(self):
        print('-' * (len(self.rows)) * 2)
        for row in self.rows:
            print(' '.join(row))
        print('-' * (len(self.rows)) * 2)


if __name__ == '__main__':
    game_in = "10 10\n..*..***.*\n**********\n.**..**.*.\n****......" + \
    "\n......*...\n..*..***.*\n**********\n.**..**.*.\n****......\n......*..."
    for t in range(100):
        next_gen = next_generation(game_in)
        game_in = next_gen
        time.sleep(0.1)