Setup Ubuntu 16.04 for GIS development postgresql 9.6, postgis 2.3, gdal 2.1.2, python 3.5, pgrouting

install-postgres-postgis-gdal.sh

sudo add-apt-repository "deb http://apt.postgresql.org/pub/repos/apt/ xenial-pgdg main"
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
sudo apt-get update
sudo apt-get install postgresql-9.6

sudo apt-get install postgresql-9.6-postgis-2.3
sudo apt-get install postgresql-9.6-pgrouting

sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable
sudo apt-get update

sudo apt install gdal-bin python3-gdal

sudo apt-get -y install python3-pip
python3 -m pip install
python3 -m pip install --upgrade pip
python3 -m pip install pytest

sudo apt-get install python3-venv

I got error when executing: sudo apt-get install postgresql-9.6-postgis-2.3
Ubuntu 16.04.6

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:
 postgresql-9.6-postgis-2.3 : Depends: libgdal1i (>= 1.9.0) but it is not going to be installed
                              Depends: liblwgeom-2.3-0 (>= 2.3.0) but it is not going to be installed
                              Depends: libsfcgal1 (>= 1.2.0) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.