Could not prepare Boot variable: No space left on device (package shim-signed 1.37~18.04.3+15+1533136590.3beb971-0ubuntu1 failed to install/upgrade: dependency problems - leaving triggers unprocessed)

I was trying to install python-pip

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: shim-signed 1.37~18.04.3+15+1533136590.3beb971-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-45.48-generic 4.15.18
Uname: Linux 4.15.0-45-generic x86_64
.proc.sys.kernel.moksbstate_disabled: Error: [Errno 2] No such file or directory: '/proc/sys/kernel/moksbstate_disabled'
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
Date: Tue Feb 5 22:15:14 2019
ErrorMessage: dependency problems - leaving triggers unprocessed
InstallationDate: Installed on 2018-09-01 (157 days ago)
InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
Python3Details: /usr/bin/python3.6, Python 3.6.7, python3-minimal, 3.6.7-1~18.04
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2.1
 apt 1.6.8
SecureBoot: 6 0 0 0 1
SourcePackage: shim-signed
Title: package shim-signed 1.37~18.04.3+15+1533136590.3beb971-0ubuntu1 failed to install/upgrade: dependency problems - leaving triggers unprocessed
UpgradeStatus: Upgraded to bionic on 2018-09-06 (152 days ago)