Dynamically add arguments in if condition in python

I am writing code for a tick-tac-toe game that uses grids. I am trying to check the condition where all the cells of a row match with each other, so that players can be declared winners. Also, I am using dynamic sizes of board (3 by 3, 4 by 4, 5 by 5....). So for this purpose, I am using if condition in a for loop. The problem is that I can't figure out a way to add arguments dynamically to the if statement. The if defined is static and I can't add the condition of the last cell of the row (if size increases from 3 by 3 to 4 by 4).

expected outcome:

3 by 3 grid:

count = 0
for i in range(dim):
    if grid[count]=="X" and grid[1+ count]=="X" and grid[2+ count]=="X":
       count1 = 0
       print ("Player X win")
       print ("-------------")
       for i in range(dim):
           print(grid[0 + count1 : dim + count1])
           count1 =+ dim
       print ("-------------")
       count += dim

I am trying to loop for all rows to check the match.

What I want is to change the if grid[count]=="X" and grid[1+ count]=="X" and grid[2+ count]=="X": to incorporate the change of the grid size from

3 by 3 to

4 by 4 if grid[count]=="X" and grid[1+ count]=="X" and grid[2+ count]=="X" and grid[3+ count]=="X":

5 by 5 if grid[count]=="X" and grid[1+ count]=="X" and grid[2+ count]=="X" and grid[3+ count]=="X" and grid[4+ count]=="X":

is there a better way to do this? Thank you!