gistfile1.py

class Student():
    def __init__(self):
        self.grade = ''
        self.name = ''
        self.sclass = ''
        self.form_teacher = ''

    def register(self, name):
        self.name = name

    def assign_class(self, sclass, teacher):
        self.sclass = sclass
        self.form_teacher = teacher

    def chat(self):
        print "hello, i'm %s from %s and my teacher is %s." % (self.name, self.sclass, self.teacher)

kenny = Student()
kenny.register('kenny')
kenny.assign_class('4B','Mr Sim')