--- a/src/pyams_utils/factory.py	Thu Jan 17 10:59:39 2019 +0100
+++ b/src/pyams_utils/factory.py	Thu Jan 17 14:23:59 2019 +0100
@@ -30,11 +30,13 @@
 
 .. code-block:: python
 
-    @implementer(IMyInterface)
     @factory_config(IMyInterface)
     class MyClass(object):
         '''Class implementing my interface'''
 
+A class declared as factory for a specific interface automatically implements the given interface.
+You can also provide a tuple or set of interfaces in "factory_config()" decorator.
+
 When a factory is registered, you can look for a factory:
 
 .. code-block:: python
@@ -51,21 +53,27 @@
 
 __docformat__ = 'restructuredtext'
 
-
-# import standard library
 import logging
-logger = logging.getLogger('PyAMS (utils)')
 
 import venusian
+from zope.component import adapter
+from zope.interface import Interface, classImplements, implementer
+from zope.interface.interface import InterfaceClass
 
-# import interfaces
 from pyams_utils.interfaces import IObjectFactory
+from pyams_utils.registry import get_global_registry
+
+logger = logging.getLogger('PyAMS (utils)')
 
-# import packages
-from pyams_utils.registry import get_global_registry
-from zope.component import adapter, queryAdapter
-from zope.interface import implementer, Interface, provider, classImplements
-from zope.interface.interface import InterfaceClass
+
+def is_interface(object):
+    """Check if given object is an interface"""
+    return issubclass(object.__class__, InterfaceClass)
+
+
+def get_interface_name(iface):
+    """Get interface full name"""
+    return iface.__module__ + '.' + iface.__name__
 
 
 @adapter(Interface)
@@ -82,16 +90,6 @@
         return self.factory()
 
 
-def is_interface(object):
-    """Check if given object is an interface"""
-    return issubclass(object.__class__, InterfaceClass)
-
-
-def get_interface_name(iface):
-    """Get interface full name"""
-    return iface.__module__ + '.' + iface.__name__
-
-
 def register_factory(interface, klass, registry=None, name=''):
     """Register factory for a given interface