Pick correct representation of doctest for function in Python.
def sum(a, b): ''' a = 1 b = 2 sum(a, b) = 3 ''' return a + b
def sum(a, b): """ >>> a = 1 >>> b = 2 >>> sum(a, b) 3 """ return a + b
def sum(a, b): """ a = 1 b = 2 sum(a, b) = 3 """ return a + b
def sum(a, b): # a = 1 # b = 2 # sum(a, b) = 3 return a + b