Checks if the given pseudo-legal move is an en passant capture.

def is_en_passant(self, move: Move) -> bool:
        """Checks if the given pseudo-legal move is an en passant capture."""
        return (self.ep_square == move.to_square and
                bool(self.pawns & BB_SQUARES[move.from_square]) and
                abs(move.to_square - move.from_square) in [7, 9] and
                not self.occupied & BB_SQUARES[move.to_square])