def parse_rectlabel_app_output(self):
        """ Internal use mostly, finds all .json files in the current folder expecting them to all have been outputted by the RectLabel app
            parses each file returning finally an array representing a csv file where each element is a row and the 1st element [0] is the
            column headers.
            Could be useful for subsequent string manipulation therefore not prefixed with an underscore
            RectLabel info: https://rectlabel.com/
        """
        # get json files only
        files = []
        files = [f for f in os.listdir() if f[-5:] == '.json']

        if len(files) == 0:
            print('No json files found in this directory')
            return None

        max_boxes = 0        
        rows = []

        for each_file in files:
            f = open(each_file, 'r')
            j = f.read()            
            j = json.loads(j)            
            f.close()

            # running count of the # of boxes.
            if len(j['objects']) > max_boxes:
                max_boxes = len(j['objects'])

            # Each json file will end up being a row
            # set labels
            row = []

            for o in j['objects']:
                labels = {}
                labels['label'] = o['label']
                labels['x'] = o['x_y_w_h'][0]
                labels['y'] = o['x_y_w_h'][1]
                labels['width'] = o['x_y_w_h'][2]
                labels['height'] = o['x_y_w_h'][3]

                # String manipulation for csv
                labels_right_format = '\"' + json.dumps(labels).replace('"', '\"\"') + '\"'

                row.append(labels_right_format)

            row.insert(0, '\"' + j['filename'] + '\"')        

            rows.append(row)

        # one array element per row
        rows = [','.join(i) for i in rows]

        header = '\"image\"'
        
        for box_num in range(0, max_boxes):
            header += ', \"box\"' + str(box_num)

        rows.insert(0, header)
        return rows
Internal use mostly, finds all .json files in the current folder expecting them to all have been outputted by the RectLabel app
            parses each file returning finally an array representing a csv file where each element is a row and the 1st element [0] is the
            column headers.
            Could be useful for subsequent string manipulation therefore not prefixed with an underscore
            RectLabel info: https://rectlabel.com/