Fix some pylint messages.

mininet/clean.py

@@ -55,7 +55,7 @@ def cleanup():
             sh( 'ovs-vsctl del-br ' + dp )
 
     info( "*** Removing all links of the pattern foo-ethX\n" )
-    links = sh( "ip link show | egrep -o '(\w+-eth\w+)'" ).split( '\n' )
+    links = sh( r"ip link show | egrep -o '(\w+-eth\w+)'" ).split( '\n' )
     for link in links:
         if link != '':
             sh( "ip link del " + link )

mininet/log.py

@@ -60,18 +60,16 @@ class Singleton( type ):
        See http://en.wikipedia.org/wiki/SingletonPattern#Python
 
        Intended to be used as a __metaclass_ param, as shown for the class
-       below.
+       below."""
 
-       Changed cls first args to mcs to satisfy pylint."""
+    def __init__( cls, name, bases, dict_ ):
+        super( Singleton, cls ).__init__( name, bases, dict_ )
+        cls.instance = None
 
-    def __init__( mcs, name, bases, dict_ ):
-        super( Singleton, mcs ).__init__( name, bases, dict_ )
-        mcs.instance = None
-
-    def __call__( mcs, *args, **kw ):
-        if mcs.instance is None:
-            mcs.instance = super( Singleton, mcs ).__call__( *args, **kw )
-            return mcs.instance
+    def __call__( cls, *args, **kw ):
+        if cls.instance is None:
+            cls.instance = super( Singleton, cls ).__call__( *args, **kw )
+            return cls.instance
 
 
 class MininetLogger( Logger, object ):

mininet/node.py

@@ -759,7 +759,7 @@ class Switch( Node ):
     def defaultDpid( self ):
         "Derive dpid from switch name, s1 -> 1"
         try:
-            dpid = int( re.findall( '\d+', self.name )[ 0 ] )
+            dpid = int( re.findall( r'\d+', self.name )[ 0 ] )
             dpid = hex( dpid )[ 2: ]
             dpid = '0' * ( self.dpidLen - len( dpid ) ) + dpid
             return dpid
@@ -787,7 +787,7 @@ class Switch( Node ):
 
     def connected( self ):
         "Is the switch connected to a controller? (override this method)"
-        return False
+        return False and self  # satisfy pylint
 
     def __repr__( self ):
         "More informative string representation"

mininet/term.py

@@ -54,7 +54,7 @@ def makeTerm( node, title='Node', term='xterm', display=None ):
 
 def runX11( node, cmd ):
     "Run an X11 client on a node"
-    display, tunnel = tunnelX11( node )
+    _display, tunnel = tunnelX11( node )
     popen = node.popen( cmd )
     return [ tunnel, popen ]