elben

@singleton
class Counter:
    def __init__(self):
        self.count = 0
    def inc(self):
        self.count += 1

print type(Counter) # <type 'function'>

elben

class OneOnly {
    private static final OneOnly the_one = new OneOnly();
    
    private OneOnly() {
    }

    public static get() {
        return the_one;
    }

elben

>>> print Counter() is Counter()
True

elben

def singleton(cls):
    instances = {}                                  # Line 2
    def getinstance():
        if cls not in instances:
            instances[cls] = cls()                  # Line 5
        return instances[cls]
    return getinstance
 
class Counter:
    def __init__(self):

elben

>>> print waztile.istitle.__doc__
S.istitle() -> bool

Return True if S is a titlecased string and there is at least one
character in S, i.e. uppercase characters may only follow uncased
characters and lowercase characters only cased ones. Return False
otherwise.

elben

>>> waztile = "not poison"
>>> type(waztile)
<type 'str'>
>>> print waztile
not poison

elben

>>> dir(waztile)
['__add__', '__class__', '__contains__', '__delattr__', '__doc__', '__eq__',
'__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__',
'__getslice__', '__gt__', '__hash__', '__init__', '__le__', '__len__',
'__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__',
'__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__',
'__sizeof__', '__str__', '__subclasshook__', '_formatter_field_name_split',
'_formatter_parser', 'capitalize', 'center', 'count', 'decode', 'encode',
'endswith', 'expandtabs', 'find', 'format', 'index', 'isalnum', 'isalpha',
'isdigit', 'islower', 'isspace', 'istitle', 'isupper', 'join', 'ljust',

elben

# unittest.py

class TestProgram:
    def __init__(...):
        ...
        self.runTests()

main = TestProgram

elben

import unittest

class TestSomething(unittest.TestCase):
    def test1(self):
        self.assert_(True)

if __name__ == '__main__':
    unittest.main()

elben

class User < ActiveRecord::Base
  attr_accessor :role
  has_many :user_roles, :dependent => :destroy
  has_many :roles, :through => :user_roles
  after_save :set_role

  def set_role
    if @role     # NOTE (A): @role is nil. I want it to be params[:user][:role].
      # NOTE (B): do stuff here, mostly:
      self.roles << @role