def __str__(self):
    grid_as_string = ''
    for i in range(self.num_columns):
        for j in range(self.num_rows):
            grid_as_string += f'{self.grid[i][j].get_value()} '
        grid_as_string += '\n'
    return grid_as_string
def __str__(self):
    grid_as_string = 
    for i in range(self.num_columns):
        for j in range(self.num_rows):
            grid_as_string += f'{self.grid[i][j].get_value()} '
        grid_as_string += '\n'
    return grid_as_string