Fail to unpack an image

[w2016561536]

The image is from https://dl.twrp.me/a70q/twrp-3.5.0_9-0-a70q.img.html

At first, I have changed name to "boot.img" but when I try to unpack , it reoprts :

arguments: [bootimg file]
bootimg file: .\boot.img
output: kernel[.gz] ramdisk[.gz] second[.gz]
found nonstandard ramdisk_addr
found nonstandard tags_addr
found device_tree_image
base: 0x0
ramdisk_addr: 0x2000000
second_addr: 0xf00000
tags_addr: 0x1e00000
page_size: 4096
name: "SRPRL06C001"
cmdline: "console=null androidboot.hardware=qcom androidboot.memcg=1 lpm_levels.sleep_disabled=1 video=vfb:640x400,bpp=32,memsize=3072000 msm_rtb.filter=0x237 service_locator.enable=1 swiotlb=1 androidboot.usbcontroller=a600000.dwc3 nokaslr printk.devkmsg=on androidboot.vbmeta.avb_version=1.0 androidboot.avb_version=1.0 buildvariant=eng"
padding_size=4096
arguments: [ramdisk file] [directory]
ramdisk file: ramdisk
directory: initrd
output: cpiolist.txt
Traceback (most recent call last):
File "", line 2213, in
File "", line 1463, in unpack_bootimg
IOError: invalid ramdisk

and fail to get ramdisk.

Could you help me to slove the problem??