example: python bindings key count

* Added script wo count the number of keys in both the public and
  secret key stores.

lang/python/examples/howto/keycount.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from __future__ import absolute_import, division, unicode_literals
+
+# Copyright (C) 2018 Ben McGinnes <ben@gnupg.org>
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation; either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License and the GNU
+# Lesser General Public Licensefor more details.
+#
+# You should have received a copy of the GNU General Public License and the GNU
+# Lesser General Public along with this program; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import gpg
+
+c = gpg.Context()
+seckeys = c.keylist(pattern=None, secret=True)
+pubkeys = c.keylist(pattern=None, secret=False)
+
+seclist = list(seckeys)
+secnum = len(seclist)
+
+publist = list(pubkeys)
+pubnum = len(publist)
+
+print("""
+Number of secret keys:  {0}
+Number of public keys:  {1}
+""".format(secnum, pubnum)