An attempt at creating a visitor design pattern in Python. Tested with Python 2.7.6

Visitor.py

"""
@Author: Sujayyendhiren Ramarao
@Description: Visitor design pattern
"""

# For creating abstract base class.
import abc

""" Add features to this class using Visitor design pattern"""
class SmartTV (object):
    def __init__(self):
        self.diagonal = 50 #Diagonal length in inches
        self.mirroring = True #Mirroring with handheld devices
        self.applicationExtensibility = True #More applications can be added to software

    def __str__(self):
        return "\n\nDiagonal length: " + str(self.diagonal) + "\nMirroring feature: " + str(self.mirroring) + "\nApplication additions: " + str(self.applicationExtensibility)

    def features(self):
        return str(self)

class AbsVisitor( object ):
    """ Abstract class for Visitor features."""
    __metaclass__ = abc.ABCMeta
    @abc.abstractmethod
    def visit(self, platform ):
        return

class AbsElement( object ):
    """ Abstract class for SmartTV new feature that implements accept """
    __metaclass__ = abc.ABCMeta
    @abc.abstractmethod
    def accept(self, input):
        return

class AddSmartFeaturesVisitor( AbsVisitor):
    """ Implementing skype video feature to SMART TV of different platforms"""

    def visit(self, platform ):
        if isinstance( platform, SmartTVAndSkypeVideoLinux):
            print("\nLinux platform ")
            self.skypeAppLinux(platform)
        elif isinstance( platform, SmartTVAndSkypeVideoIOS ):
            print("\nIOS platform")
            self.skypeAppIOS(platform)
        elif isinstance( platform, SmartTVAndSkypeVideoTizenOS ):
            print("\nTizen platform")
            self.skypeAppTizenOS(platform)

    def videoCall(self):
        print("Create video call session.")

    def skypeAppLinux(self, inp):
        print("Linux specific initialization")
        #print( isinstance(inp) )
        self.videoCall()
        print("Linux specific cleanup")

    def skypeAppIOS(self, inp):
        print("IOS specific initialization")
        self.videoCall()
        print("IOS specific cleanup")

    def skypeAppTizenOS(self, inp):
        print("Tizen specific initialization")
        self.videoCall( )
        print("Tizen specific cleanup")

class SmartTVAndSkypeVideoIOS( SmartTV , AbsElement ):

    def __init__(self):
        pass

    def accept( self, visitor ):
        visitor.visit( self )

    def __str__(self):
        return "Skype feature added in SmartTVAndSkypeVideoIOS."

class SmartTVAndSkypeVideoLinux(SmartTV , AbsElement):
    """ Smart TV for Linux"""
    def __init__(self):
        pass

    def accept( self, visitor ):
        visitor.visit( self )

    def __str__(self):
        return "Skype feature added in SmartTVAndSkypeVideoLinux."

class SmartTVAndSkypeVideoTizenOS(SmartTV , AbsElement):
    """ Smart TV for TizenOS """
    def __init__(self):
       pass

    def accept( self, visitor ):
        visitor.visit( self )

    def __str__(self):
        return "Skype feature added in SmartTVAndSkypeVideoTizenOS."

if __name__ == "__main__":

    smartTV = SmartTVAndSkypeVideoIOS()
    visitor = AddSmartFeaturesVisitor()

    #New feature accessed for IOS
    smartTV.accept( visitor )

    smartTV = SmartTVAndSkypeVideoLinux()
    #New feature accessed for Linux
    smartTV.accept( visitor )

    smartTV = SmartTVAndSkypeVideoTizenOS()
    #New feature accessed for TizenOS
    smartTV.accept( visitor )