How to prevent a move further when a piece is found on the board?

Question

Python

I'm trying to make it so that when a piece is detected, the next move is impossible, since it will already be a jump.
Board
board = [['bluerook', ' ', ' ', ' ', 'bluepawn', ' ', ' ', ' '],
['bluepawn', ' ', ' ' ', ' ', ' ', ' ', ' ', ' '],
[' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ']]]

class bluerook(self.x, self.y, moveX, moveY, cell):
    """ self.x, self.y - where piece now
        moveX, moveY, - where piece can be dragged
        cell - where piece can be dragged
    """
    rule = None
    piece_on_my_way = False

    if self.x == moveX:
        while rule is None:
            if cell != ' ' and not piece_on_my_way:
                piece_on_my_way = True
            elif cell == ' ' and not piece_on_my_way:
                rule = True

            while piece_on_my_way:
                if cell = ' ':
                    rule = False
                elif cell != ' ':
                    rule = False
        return rule