diff --git a/netarch/__init__.py b/netarch/__init__.py
index 6317f23..73ff574 100644
--- a/netarch/__init__.py
+++ b/netarch/__init__.py
@@ -75,6 +75,7 @@ dbch  = (u'·☺☻♥♦♣♠•◘○◙♂♀♪♫☼'
          u'αßΓπΣσµτΦΘΩδ∞φε∩'
          u'⁰¹²³⁴⁵⁶⁷⁸⁹ⁱⁿ⁽⁼⁾¤')
 
+
 def unpack(fmt, buf):
     """Unpack buf based on fmt, return the rest as a string."""
 
diff --git a/netarch/crypto.py b/netarch/crypto.py
index c6f860d..52f9a56 100644
--- a/netarch/crypto.py
+++ b/netarch/crypto.py
@@ -138,7 +138,7 @@ def freqgraph(f):
             return 0
     items = []
     for c, n in f.iteritems():
-        if type(n) != type(0):
+        if not isinstance(n, int):
             n = len(n)
         items.append((c, n))
     items.sort(cmp2)
@@ -171,8 +171,7 @@ def rot(n, txt):
     for c in txt:
         if c.isalpha():
             o = ord(c) + n
-            if ((c.islower() and o > ord('z')) or
-                (c.isupper() and o > ord('Z'))):
+            if ((c.islower() and o > ord('z')) or (c.isupper() and o > ord('Z'))):
                 o -= 26
             out += chr(o)
         else:
@@ -223,7 +222,7 @@ def adds(txt):
 class XorMask(object):
     def __init__(self, mask, stick=False):
         self.offset = 0
-        if type(mask) == type(''):
+        if isinstance(mask, str):
             self._mask = tuple(ord(m) for m in mask)
         else:
             self._mask = tuple(mask)
diff --git a/netarch/ip.py b/netarch/ip.py
index c34127e..126e8c7 100644
--- a/netarch/ip.py
+++ b/netarch/ip.py
@@ -159,9 +159,10 @@ class Frame(object):
                  len(self.payload)))
 
     def __arp_repr__(self):
-        return '<Frame %s %s(%s) -> %s(%s)>' % (self.name,
-                                        str_of_eth(self.ar_sha), self.src_addr,
-                                        str_of_eth(self.ar_tha), self.dst_addr)
+        return '<Frame %s %s(%s) -> %s(%s)>' % (
+            self.name,
+            str_of_eth(self.ar_sha), self.src_addr,
+            str_of_eth(self.ar_tha), self.dst_addr)
 
 
 class TCP_Recreate(object):
@@ -601,7 +602,7 @@ class Packet(UserDict.DictMixin):
         """Handle data from a Session class."""
 
         data = self.parse(data)
-        if self.opcode != None:
+        if self.opcode is not None:
             try:
                 f = getattr(self, 'opcode_%s' % self.opcode)
             except AttributeError: