diff --git a/pygal/ghost.py b/pygal/ghost.py
index 585df2a..53f58db 100644
--- a/pygal/ghost.py
+++ b/pygal/ghost.py
@@ -61,8 +61,13 @@ class Ghost(object):
         self.series.append(
             Serie(title, values, len(self.series), self.cls.__value__))
 
+    def _check(self):
+        if self.config.logarithmic and self.config.zero == 0:
+            self.config.zero = 1
+
     def make_instance(self):
         self.config(**self.__dict__)
+        self._check()
         self._last__inst = self.cls(self.config, self.series)
         return self._last__inst
 
diff --git a/pygal/graph/base.py b/pygal/graph/base.py
index 880a409..e97d51d 100644
--- a/pygal/graph/base.py
+++ b/pygal/graph/base.py
@@ -44,18 +44,10 @@ class BaseGraph(object):
         self.svg = Svg(self)
         self._x_labels = None
         self._y_labels = None
-        self._box = None
         self.nodes = {}
-        self.margin = None
-        self.view = None
-
-    def reinit(self):
-        """(Re-)Init the graph"""
         self.margin = Margin(*([20] * 4))
         self._box = Box()
-        if self.logarithmic and self.zero == 0:
-            # If logarithmic, default zero to 1
-            self.zero = 1
+        self.view = None
 
     def __getattr__(self, attr):
         """Search in config, then in self"""
@@ -79,12 +71,12 @@ class BaseGraph(object):
         if self.show_legend:
             h, w = get_texts_box(
                 map(lambda x: truncate(x, self.truncate_legend or 15),
-                  cut(self.series, 'title')),
+                    cut(self.series, 'title')),
                 self.legend_font_size)
             if self.legend_at_bottom:
                 h_max = max(h, self.legend_box_size)
                 self.margin.bottom += 10 + h_max * round(
-                        sqrt(len(self.series)) - 1) * 1.5 + h_max
+                    sqrt(len(self.series)) - 1) * 1.5 + h_max
             else:
                 self.margin.right += 10 + w + self.legend_box_size
 
@@ -121,7 +113,7 @@ class BaseGraph(object):
         return [val
                 for serie in self.series
                 for val in serie.values
-                if val != None]
+                if val is not None]
 
     @cached_property
     def _len(self):
@@ -170,13 +162,11 @@ class BaseGraph(object):
                 serie.metadata += diff * [self.__value__(0)]
 
             for metadata in serie.metadata:
-                if metadata.value == None:
+                if metadata.value is None:
                     metadata.value = 0
 
     def _render(self):
         """Make the graph internally"""
-        self.reinit()
-        self.svg.reinit()
         if self._has_data():
             self._draw()
             self.svg.pre_render(False)
diff --git a/pygal/svg.py b/pygal/svg.py
index 95d560e..c40b9a1 100644
--- a/pygal/svg.py
+++ b/pygal/svg.py
@@ -25,6 +25,7 @@ from __future__ import division
 import io
 import os
 import json
+from datetime import date
 from lxml import etree
 from math import cos, sin, pi
 from urlparse import urlparse
@@ -40,19 +41,16 @@ class Svg(object):
         self.graph = graph
         self.processing_instructions = [
             etree.PI(u'xml', u"version='1.0' encoding='utf-8'")]
-        self.root = None
-        self.defs = None
-
-    def reinit(self):
-        """(Re-)initialization"""
         self.root = etree.Element(
             "{%s}svg" % self.ns,
             nsmap={
                 None: self.ns,
                 'xlink': 'http://www.w3.org/1999/xlink',
             })
-        self.root.append(etree.Comment(
-            u'Generated with pygal %s ©Kozea 2012' % __version__))
+        self.root.append(
+            etree.Comment(u'Generated with pygal %s ©Kozea 2012 on %s' % (
+                __version__, date.today().isoformat())))
+        self.root.append(etree.Comment(u'http://pygal.org'))
         self.root.append(etree.Comment(u'http://github.com/Kozea/pygal'))
         self.defs = self.node(tag='defs')
 
@@ -135,7 +133,8 @@ class Svg(object):
         self.node(node, 'path',
                   d=root % (origin, line), **kwargs)
 
-    def slice(self, serie_node, node, radius, small_radius,
+    def slice(
+            self, serie_node, node, radius, small_radius,
             angle, start_angle, center, val):
         """Draw a pie slice"""
         project = lambda rho, alpha: (
@@ -144,14 +143,14 @@ class Svg(object):
         fmt = lambda x: '%f %f' % x
         get_radius = lambda r: fmt(tuple([r] * 2))
         absolute_project = lambda rho, theta: fmt(
-                diff(center, project(rho, theta)))
+            diff(center, project(rho, theta)))
 
         if angle == 2 * pi:
             self.node(node, 'circle',
-                          cx=center[0],
-                          cy=center[1],
-                          r=radius,
-                          class_='slice reactive tooltip-trigger')
+                      cx=center[0],
+                      cy=center[1],
+                      r=radius,
+                      class_='slice reactive tooltip-trigger')
         else:
             to = [absolute_project(radius, start_angle),
                   absolute_project(radius, start_angle + angle),
@@ -165,7 +164,7 @@ class Svg(object):
                           get_radius(small_radius), int(angle > pi), to[3]),
                       class_='slice reactive tooltip-trigger')
         x, y = diff(center, project(
-                (radius + small_radius) / 2, start_angle + angle / 2))
+            (radius + small_radius) / 2, start_angle + angle / 2))
 
         self.graph._tooltip_data(node, val, x, y, classes="centered")
         self.graph._static_value(serie_node, val, x, y)
@@ -181,9 +180,9 @@ class Svg(object):
             self.root.set('height', str(self.graph.height))
         if no_data:
             no_data = self.node(self.root, 'text',
-            x=self.graph.width / 2,
-            y=self.graph.height / 2,
-            class_='no_data')
+                                x=self.graph.width / 2,
+                                y=self.graph.height / 2,
+                                class_='no_data')
             no_data.text = self.graph.no_data_text
 
     def render(self, is_unicode=False, pretty_print=False):