getPrinterAttributes causes memory usage increase

[believe2end]

Recently I use this ARM board as a print box : Orange Pi Zero2
The OS is Debian
When I test this code:

import cups as cp                                                                                                                                                                                               
import time
import tracemalloc

tracemalloc.start()
cn = cp.Connection()
while True:
    time.sleep(1)
    snapshot1 = tracemalloc.take_snapshot()
    cn.getPrinterAttributes("Canon_G5080_series")
    time.sleep(1)


    snapshot2 = tracemalloc.take_snapshot()
    top_stats = snapshot2.compare_to(snapshot1, 'lineno')
    print("[ Top 10 differences ]")
    for stat in top_stats[:10]:
            print(stat)

    top_stats = snapshot2.statistics('traceback')

    # pick the biggest memory block
    stat = top_stats[0]
    print("%s memory blocks: %.1f KiB" % (stat.count, stat.size / 1024))
    for line in stat.traceback.format():
            print(line)

I found the memory usage keeps increase:

This is the log file memory_increase.log

This is my system&&cpus info: