isAprioriValidExit([x1, y1], [x2, y2], color2) {
const color1 = this.getColor(x1, y1);
const pawnShift = (color1 == 'w' ? -1 : 1);
isAprioriValidExit([x1, y1], [x2, y2], color2) {
const color1 = this.getColor(x1, y1);
const pawnShift = (color1 == 'w' ? -1 : 1);