firewall: "if not x" is better than "if x is None" (for maat)

firewall/fields.py

@@ -37,7 +37,7 @@ add_introspection_rules([], ["firewall\.fields\.MACAddressField"])
 
 def val_alfanum(value):
     """Validate whether the parameter is a valid alphanumeric value."""
-    if alfanum_re.match(value) is None:
+    if not alfanum_re.match(value):
         raise ValidationError(_(u'%s - only letters, numbers, underscores '
             'and hyphens are allowed!') % value)
 

firewall/fw.py

@@ -44,7 +44,7 @@ class Firewall:
         self.RULES_NAT.append(s)
 
     def host2vlan(self, host, rule):
-        if rule.foreign_network is None:
+        if not rule.foreign_network:
             return
 
         if self.IPV6 and host.ipv6:
@@ -77,7 +77,7 @@ class Firewall:
 
 
     def fw2vlan(self, rule):
-        if rule.foreign_network is None:
+        if not rule.foreign_network:
             return
 
         dport_sport = self.dportsport(rule)
@@ -93,7 +93,7 @@ class Firewall:
                         'LOG_ACC' if rule.accept else 'LOG_DROP'))
 
     def vlan2vlan(self, l_vlan, rule):
-        if rule.foreign_network is None:
+        if not rule.foreign_network:
             return
 
         dport_sport = self.dportsport(rule)

firewall/models.py

@@ -164,7 +164,7 @@ class Host(models.Model):
                 "address as your own IPv4."))
         self.full_clean()
         super(Host, self).save(*args, **kwargs)
-        if id is None:
+        if not id:
             Record(domain=self.vlan.domain, host=self, type='A',
                     owner=self.owner).save()
             if self.ipv6:
@@ -270,14 +270,14 @@ class Record(models.Model):
                     raise ValidationError(_("Can't specify name for "
                         "A or AAAA records if host is set!"))
             elif self.type == 'CNAME':
-                if self.name is None:
+                if not self.name:
                     raise ValidationError(_("Name must be specified for "
                         "CNAME records if host is set!"))
                 if self.address:
                     raise ValidationError(_("Can't specify address for "
                         "CNAME records if host is set!"))
         else:    # if self.host is None
-            if self.address is None:
+            if not self.address:
                 raise ValidationError(_("Address must be specified!"))
 
             if self.type == 'A':
@@ -304,10 +304,10 @@ class Record(models.Model):
             else:
                 return self.name
         else:    # if self.host is None
-            if not self.name:
-                return unicode(self.domain)
-            else:
+            if self.name:
                 return self.name + '.' + unicode(self.domain)
+            else:
+                return unicode(self.domain)
 
     def __get_address(self):
         if self.host:
@@ -327,7 +327,7 @@ class Record(models.Model):
         address = self.__get_address()
         if self.host and self.type == 'AAAA' and not self.host.ipv6:
             return None
-        elif address is None or name is None:
+        elif not address or not name:
             return None
         else:
             return {'name': name,