Python Global Variable - Singelton Pattern

Singelton.py

class Mojtaba:
    SharedVariable = {}
    def __init__(self):
        self.MyDict = self.SharedVariable
  


if __name__=='__main__':

    a = Mojtaba()
    b = Mojtaba()
    user1 = {}
    user1["fn"] = "ali"
    user1["ln"] = "alavi"

    a.MyDict[0] = user1
    print "a >> "
    print a.MyDict
    print "b >>"
    print b.MyDict

    user2={}
    user2["fn"] = "ali"
    user2["ln"] = "alavi"

    b.MyDict[1] = user2
    print "a >> "
    print a.MyDict
    print "b >>"
    print b.MyDict