get pitch data
        :param soup: Beautifulsoup object
        :param pa: atbat data for plate appearance
        :return: pitches result(list)

def _get_pitch(self, soup, pa):
        """
        get pitch data
        :param soup: Beautifulsoup object
        :param pa: atbat data for plate appearance
        :return: pitches result(list)
        """
        pitches = []
        ball_tally, strike_tally = 0, 0
        for pitch in soup.find_all('pitch'):
            # pitching result
            pitch = Pitch.row(pitch, pa, pitches, ball_tally, strike_tally)
            pitches.append(pitch)
            # ball count
            ball_tally, strike_tally = RetroSheet.ball_count(ball_tally, strike_tally, pitch['pitch_res'])
        return pitches