# Learn Classes and Objects by Building a Sudoku Solver - Step 19

Next, you will create a string representation of the row with spaces between each element.
For that, outside the innermost `for` loop body, create a string `row`. Assign the following formatted string `f'║ {" ".join(row_list)} ║\n'` to it to join the elements of `row_list` with a space in between.

create a string `row`

Isn’t row a variable?

``````class Board:
def __init__(self, board):
self.board = board

def __str__(self):
upper_lines = f'\n╔═══{"╤═══"*2}{"╦═══"}{"╤═══"*2}{"╦═══"}{"╤═══"*2}╗\n'
middle_lines = f'╟───{"┼───"*2}{"╫───"}{"┼───"*2}{"╫───"}{"┼───"*2}╢\n'
lower_lines = f'╚═══{"╧═══"*2}{"╩═══"}{"╧═══"*2}{"╩═══"}{"╧═══"*2}╝\n'
board_string = upper_lines

for index, line in enumerate(self.board):
row_list = []

# User Editable Region

for square_no, part in enumerate([line[:3], line[3:6], line[6:]], start=1):
row_square = '|'.join(str(item) for item in part)
row_list.extend(row_square)

if square_no != 3:
row_list.append('║')

# User Editable Region

``````

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36`

### Challenge Information:

Learn Classes and Objects by Building a Sudoku Solver - Step 19

Welcome to the forum @Mazi

Here is the error message:

Assign the formatted string `f'║ {" ".join(row_list)} ║\n'` to a variable named `row`.

The variable you are asked to declare is `row`.
The variable is assigned the value of the formatted `string`.

Happy coding