python functions generators closures decorators

Types of arguments:

#default values: 
    def sub1( a,b='default',i=0)

named arguments 
def info(spacing=15, object=odbchelper): 

tuple (args,params) 
    def sumsq2(*a): return sum(x*x for x in a)

dictionary 
    def sumsq2(**a):



generators in python - used yield insted of return 
def fibonacci()
 i=j=1
 while True:
  r,i,j = i,j,i+j
  yield r


  for rabbits in fibonacci():
    print rabbits
    if rabbit > 100 : break
    >>
    1 1 2 3 5 8 13 21 34 55 89 144

Closures    
def makeAdder(addend):
    def adder(augend):
        return audend + addend
    return adder


a23=MakeAdder(23)
a42=MakeAdder(42)

print a23(100) , a42(100) , a23(a42(100))
>> 123 142 165


decorators

@<decor>
def <name>
#is like 
 def (name)
    name = <decor>(<name>)


#or another example 
@dec2
@dec1
def func(arg1, arg2, ...):
    pass

#This is equivalent to:

def func(arg1, arg2, ...):
    pass
func = dec2(dec1(func))

 and singleton example 
def singleton(cls):
    instances = {}
    def getinstance():
        if cls not in instances:
            instances[cls] = cls()
        return instances[cls]
    return getinstance

@singleton
class MyClass:
    ...

more...