Connect Four Win Check Function

[ShadowWarrior17]

I am creating a Connect Four game and was wondering on how to create a function to determine if a player has won.

This is my board:

"|   |   |   |   |   |   |   |"
"|   |   |   |   |   |   |   |"
"|   |   |   |   |   |   |   |"
"|   |   |   |   |   |   |   |"
"|   |   |   |   |   |   |   |"
"|   |   |   |   |   |   |   |"

The nth term between each counter space is 4n-2.

I have started with something like this:

def wincheck(alist):
    x=0
    y=0
    pos=(4*x)-2

My board is stored as a 2d array, so the function will use that.

Any suggestions?