When i run this program i get an error that MinimaxNode' object has no attribute 'value'

ConnectFour is an other class that initializes the board and marks the moves, checks if someone won, etc.
Utility just returns 2 points (it is still in progress)

The problem arises that in MinimaxPlayer in child.get\_minimax\_value as it puts an error that MinimaxNode' object has no attribute 'value'