For another perspective, Jack Diederich gave a talk at PyCon 2012 called "Stop Writing Classes".
One of his examples is the class with a single method, which he suggests should be just a function. If the idea is to set up an object containing a load of data and a single method that can be called later (perhaps many times) to act on that data, then you can still do that with a regular function by making an inner function the return value.
Something like:
def complicated(a, b, c, d, e):
def inner(k):
return (a*k, b*k, c*k, d*k, e*k)
return inner
foo = complicated(1, 2, 3, 4, 5)
result = foo(100)
This does seem much simpler to me than:
class Complicated:
def __init__(self, a, b, c, d, e):
self.a = a
self.b = b
self.c = c
self.d = d
self.e = e
def calc(self, k)
return (self.a*k, self.b*k, self.c*k, self.d*k, self.e*k)
foo = Complicated(1, 2, 3, 4, 5)
result = Complicated.calc(100)
The main limitation of the function based approach is that you cannot read back the values of a, b, c, d, and e in the example.