I updagraded Ubuntu and kile and okular packages were lost and imposible to install because "The following packages have unmet dependencies: python-qt4 and python-qt4-sql"

[Irelka Colina Moreno]

$ sudo apt install okular

Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 python-qt4 : Depends: libqt4-dbus (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-declarative (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-designer (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-help (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-network (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-script (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-scripttools (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-svg (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-test (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-xml (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqt4-xmlpatterns (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqtassistantclient4 (>= 4.6.3) but it is not going to be installed
              Depends: libqtcore4 (>= 4:4.8.0-1~) but it is not going to be installed
              Depends: libqtgui4 (>= 4:4.8.0-1~) but it is not going to be installed
 python-qt4-sql : Depends: libqt4-sql (>= 4:4.8.0-1~) but it is not going to be installed
                  Depends: libqtcore4 (>= 4:4.8.0-1~) but it is not going to be installed
                  Depends: libqtgui4 (>= 4:4.8.0-1~) but it is not going to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:20.04.28
ProcVersionSignature: Ubuntu 5.4.0-54.60-generic 5.4.65
Uname: Linux 5.4.0-54-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.12
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Tue Nov 24 20:35:11 2020
InstallationDate: Installed on 2018-09-20 (796 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to focal on 2020-11-24 (0 days ago)
VarLogDistupgradeTermlog: