@@ -1,5 +1,25 @@

+#

+# Copyright 2008-2017 Jose Fonseca

+#

+# 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 3 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 Lesser General Public License for more details.

+#

+# You should have received a copy of the GNU Lesser General Public License

+# along with this program.  If not, see <http://www.gnu.org/licenses/>.

+#

+

 '''Visualize dot graphs via the xdot format.'''

+import sys

+assert sys.version_info.major >= 3

+

 __all__ = ['dot', 'ui']

 from . import dot

@@ -1,6 +1,6 @@

 #!/usr/bin/env python3

 #

-# Copyright 2008-2015 Jose Fonseca

+# Copyright 2008-2017 Jose Fonseca

 #

 # 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

@@ -15,6 +15,7 @@

 # You should have received a copy of the GNU Lesser General Public License

 # along with this program.  If not, see <http://www.gnu.org/licenses/>.

 #

+

 import argparse

 import sys