class SimpleClass:
    var1 = 1
    field2 = 'cat'
    def set_var1(self, value):
            print('inside set_var1')
            self.var1 = value
    def method1():
            print('method1')
    def set_field2(value, self):
            self.field2 = value

a = SimpleClass()
a.set_field2('dog')
print(a.field2)