Unmet dependency Ubuntu 15.10

I am trying to install postgresql-9.5 on Ubuntu 15.10 but I am getting an
unmet dependency.

cat /etc/apt/sources.list.d/pgdg.list
deb http://apt.postgresql.org/pub/repos/apt/ wily-pgdg main

4.2.0-23-generic #28-Ubuntu SMP

~/r/a/src> sudo apt-get install postgresql-9.5
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-9.5 : Depends: postgresql-client-9.5
Depends: postgresql-common (>= 142~) but it is not going
to be installed
E: Unable to correct problems, you have held broken packages.

~/r/a/src> sudo apt-get install postgresql-common
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-common : Depends: postgresql-client-common (>= 172.pgdg15.10+1)
but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

~/r/a/src> sudo apt-get install postgresql-client-common
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-client-common : Depends: pgdg-keyring but it is not installable
E: Unable to correct problems, you have held broken packages.

~/r/a/src> sudo apt-get install pgdg-keyring
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package pgdg-keyring is not available, but is referred to by another
package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'pgdg-keyring' has no installation candidate