--- a/src/pyams_i18n/interfaces/__init__.py	Fri Feb 22 12:32:18 2019 +0100
+++ b/src/pyams_i18n/interfaces/__init__.py	Fri Feb 22 12:32:39 2019 +0100
@@ -12,14 +12,8 @@
 
 __docformat__ = 'restructuredtext'
 
-
-# import standard library
-
-# import interfaces
-from zope.interface import Interface, invariant, Invalid
-
-# import packages
-from zope.schema import Choice, Set, Bool, List
+from zope.interface import Interface, Invalid, invariant
+from zope.schema import Bool, Choice, List, Set
 
 from pyams_i18n import _
 
@@ -70,6 +64,10 @@
     def get_language(self, request):
         """Return the matching language to use.
 
+        If 'lang' parameter is defined into request, this lang is returned.
+        Otherwise, returned language is based on browser settings, user's session or
+        server's language, depending on negotiator's settings.
+
         If no match is found, None is returned.
         """