Trouble installing frappe/bench on a fresh Ubuntu 16.04.02

I’m following the Easy Install at GitHub - frappe/bench: CLI to manage Multi-tenant deployments for Frappe apps and so I run ‘sudo python install.py --develop --user frappe’. I receive this error:

TASK [Add apt key for mariadb for Ubuntu >= 16.04] *****************************
ok: [localhost]

TASK [Add apt repository] ******************************************************
ok: [localhost]

TASK [Unattended package installation] *****************************************
changed: [localhost]

TASK [apt-get install] *********************************************************
failed: [localhost] (item=[u'mariadb-server', u'mariadb-client', u'mariadb-common', u'libmariadbclient-dev']) => {"cache_update_time": 1492026566, "cache_updated": true, "failed": true, "item": ["mariadb-server", "mariadb-client", "mariadb-common", "libmariadbclient-dev"], "msg": "'/usr/bin/apt-get -y -o \"Dpkg::Options::=--force-confdef\" -o \"Dpkg::Options::=--force-confold\" install 'mariadb-client' 'libmariadbclient-dev'' failed: E: Unable to correct problems, you have held broken packages.\n", "stderr": "E: Unable to correct problems, you have held broken packages.\n", "stdout": "Reading package lists...\nBuilding dependency tree...\nReading state information...\nSome packages could not be installed. This may mean that you have\nrequested an impossible situation or if you are using the unstable\ndistribution that some required packages have not yet been created\nor been moved out of Incoming.\nThe following information may help to resolve the situation:\n\nThe following packages have unmet dependencies:\n mariadb-client : Depends: mariadb-client-10.1 (= 10.1.22+maria-1~xenial) but it is not going to be installed\n", "stdout_lines": ["Reading package lists...", "Building dependency tree...", "Reading state information...", "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:", " mariadb-client : Depends: mariadb-client-10.1 (= 10.1.22+maria-1~xenial) but it is not going to be installed"]}
to retry, use: --limit @develop/install.retry

PLAY RECAP *********************************************************************
localhost : ok=12 changed=1 unreachable=0 failed=1

Traceback (most recent call last):
File "install.py", line 351, in 
install_bench(args)
File "install.py", line 108, in install_bench
run_playbook('develop/install.yml', sudo=True, extra_vars=extra_vars)
File "install.py", line 301, in run_playbook
success = subprocess.check_call(args, cwd=os.path.join(cwd, 'playbooks'))
File "/usr/lib/python2.7/subprocess.py", line 541, in check_call
raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['ansible-playbook', '-c', 'local', 'develop/install.yml', '-e', '@/tmp/extra_vars.json', '--become', '--become-user=frappe']' returned non-zero exit status 2

Any idea how to fix it?

It seems that my MariaDB was installed wrongly, so I removed it and ran the script again, now successfully.