Class2.py

class Complex:
    def __init__(self, real, imag, name):
        self.r = real
        self.i = imag
        self.name = name
    name = 'Complex_default'
    r = 0.0
    i = 1.1
    doc = "default doc"
    def foo(self, num):
        self.r = self.r + num

x = Complex(1.0, 3,5)

Complex.foo(x, 5)
print(x.r)