package_hook crashed with FileNotFoundError in makedirs(): [Errno 2] No such file or directory: '//var/cache/apt/archives/partial'

Traceback (most recent call last):
  File "/usr/share/apport/package_hook", line 47, in <module>
    pr.add_package(options.package)
  File "/usr/lib/python3/dist-packages/apport/report.py", line 297, in add_package
    version = packaging.get_version(package)
  File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 133, in get_version
    pkg = self._apt_pkg(package)
  File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 126, in _apt_pkg
    return self._cache()[package]
  File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 91, in _cache
    self._apt_cache = apt.Cache(progress, rootdir='/')
  File "/usr/lib/python3/dist-packages/apt/cache.py", line 134, in __init__
    self._check_and_create_required_dirs(rootdir)
  File "/usr/lib/python3/dist-packages/apt/cache.py", line 167, in _check_and_create_required_dirs
    os.makedirs(rootdir + d)
  File "/usr/lib/python3.6/os.py", line 220, in makedirs
    mkdir(name, mode)
FileNotFoundError: [Errno 2] No such file or directory: '//var/cache/apt/archives/partial'

ProblemType: Crash
DistroRelease: Ubuntu 18.10
Package: apport 2.20.10-0ubuntu9
ProcVersionSignature: Ubuntu 4.17.0-9.10-generic 4.17.17
Uname: Linux 4.17.0-9-generic x86_64
ApportVersion: 2.20.10-0ubuntu9
Architecture: amd64
CrashReports:
 600:0:117:477532:2018-08-30 21:37:16.894364432 +0530:2018-08-30 22:00:45.845285436 +0530:/var/crash/autofs.0.crash
 640:0:117:20449:2018-08-30 21:37:16.574347496 +0530:2018-08-30 21:37:17.574347496 +0530:/var/crash/_usr_share_apport_package_hook.0.crash
 600:0:117:211775:2018-08-30 22:02:54.401198146 +0530:2018-08-30 22:04:08.651412758 +0530:/var/crash/ttf-mscorefonts-installer.0.crash
 640:1000:117:2161231:2018-08-31 19:00:33.207204658 +0530:2018-08-31 19:00:30.443132877 +0530:/var/crash/_usr_bin_Xwayland.1000.crash
Date: Thu Aug 30 21:37:17 2018
ExecutablePath: /usr/share/apport/package_hook
InstallationDate: Installed on 2018-04-28 (125 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
InterpreterPath: /usr/bin/python3.6
PackageArchitecture: all
ProcCmdline: /usr/bin/python3 /usr/share/apport/package_hook -p 522-autofs --tags dist-upgrade -l /var/log/dist-upgrade/apt.log -l /var/log/dist-upgrade/apt-term.log -l /var/log/dist-upgrade/apt-clone_system_state.tar.gz -l /var/log/dist-upgrade/history.log -l /var/log/dist-upgrade/lspci.txt -l /var/log/dist-upgrade/main.log -l /var/log/dist-upgrade/term.log -l /var/log/dist-upgrade/screenlog.0 -l /var/log/dist-upgrade/xorg_fixup.log
ProcEnviron:
 TERM=screen.xterm-256color
 SHELL=/bin/bash
 LANG=en_IN
 PATH=(custom, user)
Python3Details: /usr/bin/python3.6, Python 3.6.6+, python3-minimal, 3.6.6-1
PythonArgs: ['/usr/share/apport/package_hook', '-p', '522-autofs', '--tags', 'dist-upgrade', '-l', '/var/log/dist-upgrade/apt.log', '-l', '/var/log/dist-upgrade/apt-term.log', '-l', '/var/log/dist-upgrade/apt-clone_system_state.tar.gz', '-l', '/var/log/dist-upgrade/history.log', '-l', '/var/log/dist-upgrade/lspci.txt', '-l', '/var/log/dist-upgrade/main.log', '-l', '/var/log/dist-upgrade/term.log', '-l', '/var/log/dist-upgrade/screenlog.0', '-l', '/var/log/dist-upgrade/xorg_fixup.log']
PythonDetails: N/A
SourcePackage: apport
Title: package_hook crashed with FileNotFoundError in makedirs(): [Errno 2] No such file or directory: '//var/cache/apt/archives/partial'
UpgradeStatus: Upgraded to cosmic on 2018-08-30 (0 days ago)
UserGroups: