尝试升级 python 时子进程 /usr/bin/dpkg 返回错误代码 (1)？

Question

我目前正在运行 Ubuntu 16.04，并且正在运行 python 版本 2.7.12。我正在尝试将其升级到 python 3。因此我运行以下命令：

1. sudo add-apt-repository ppa:deadsnakes/ppa。
2. sudo apt-get 更新
3. sudo apt-get 安装 python3.6

当我运行第三个命令时，收到以下错误消息：-

linux-headers-4.4.0-176 linux-headers-4.4.0-176-generic linux-headers-4.4.0-177 linux-headers-4.4.0-177-generic linux-headers-4.4.0-178 linux-headers-4.4.0-178-generic
  linux-headers-4.4.0-179 linux-headers-4.4.0-179-generic linux-headers-4.4.0-184 linux-headers-4.4.0-184-generic linux-image-4.4.0-157-generic linux-image-4.4.0-173-generic
  linux-image-4.4.0-174-generic linux-image-4.4.0-176-generic linux-image-4.4.0-177-generic linux-image-4.4.0-178-generic linux-image-4.4.0-179-generic linux-image-4.4.0-184-generic
  linux-modules-4.4.0-157-generic linux-modules-4.4.0-173-generic linux-modules-4.4.0-174-generic linux-modules-4.4.0-176-generic linux-modules-4.4.0-177-generic
  linux-modules-4.4.0-178-generic linux-modules-4.4.0-179-generic linux-modules-4.4.0-184-generic linux-modules-extra-4.4.0-157-generic linux-modules-extra-4.4.0-173-generic
  linux-modules-extra-4.4.0-174-generic linux-modules-extra-4.4.0-176-generic linux-modules-extra-4.4.0-177-generic linux-modules-extra-4.4.0-178-generic
  linux-modules-extra-4.4.0-179-generic linux-modules-extra-4.4.0-184-generic
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 93 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] Y
Setting up linux-image-4.4.0-185-generic (4.4.0-185.215) ...
I: /initrd.img.old is now a symlink to boot/initrd.img-4.4.0-185-generic
Setting up linux-image-4.4.0-186-generic (4.4.0-186.216) ...
I: /initrd.img is now a symlink to boot/initrd.img-4.4.0-186-generic
Processing triggers for linux-image-4.4.0-185-generic (4.4.0-185.215) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-4.4.0-185-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.

gzip: stdout: No space left on device
E: mkinitramfs failure find 141 cpio 141 gzip 1
update-initramfs: failed for /boot/initrd.img-4.4.0-185-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error processing package linux-image-4.4.0-185-generic (--configure):
 subprocess installed post-installation script returned error exit status 1
Processing triggers for linux-image-4.4.0-186-generic (4.4.0-186.216) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-4.4.0-186-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.

gzip: stdout: No space left on device
E: mkinitramfs failure find 141 cpio 141 gzip 1
update-initramfs: failed for /boot/initrd.img-4.4.0-186-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error processing package linux-image-4.4.0-186-generic (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 linux-image-4.4.0-185-generic
 linux-image-4.4.0-186-generic
E: Sub-process /usr/bin/dpkg returned an error code (1)

我不太清楚我做错了什么。我是新手，所以请原谅任何幼稚的错误。任何帮助都将不胜感激。谢谢。