inset batch picture into ppt

from pptx import Presentation
from pptx.util import Inches
from pptx.util import Length

def insert_chart_ppt(test_items):
    prs = Presentation()

    # left = 0  # this is x axis
    # top = 0  # this is y axis
    row_count = 3
    column_count = 4
    width = prs.slide_width / getattr(Length, "_EMUS_PER_INCH")
    height = prs.slide_height / getattr(Length, "_EMUS_PER_INCH")
    row_height = (height - 0.5) / row_count
    column_width = (width - 0.5) / column_count

    # () means generator, if generator is used out, you can't use it again
    rows = list(x * row_height for x in range(row_count))
    columns = list(y * column_width for y in range(column_count))

    img_paths = []
    for item in test_items:
        img_paths.append("analog_" + item.desc + ".png")
        if len(img_paths) == row_count * column_count:
            batch_insert(img_paths, prs, rows, columns)
            img_paths.clear()

    if len(img_paths) > 0:
        batch_insert(img_paths, prs, rows, columns)

    prs.save('chart_insert.pptx')
 
 def batch_insert(img_paths, prs, rows, columns):
    blank_slide_layout = prs.slide_layouts[6]
    slide = prs.slides.add_slide(blank_slide_layout)

    pic_width = Inches(3)
    pic_height = Inches(2.27)

    for row_index, row in enumerate(rows):
        for columns_index, column in enumerate(columns):
            index = row_index*len(columns) + columns_index
            if index < len(img_paths):
                img_path = img_paths[index]
                print("Insert {} into ppt".format(img_path))
                slide.shapes.add_picture(img_path, Inches(column), Inches(row), height=pic_height, width=pic_width)