python : understaning partial functions -

i trying head around snippet :

def a_func(a, b, c):   print "a: %s\nb: %s\nc: %s" %(a, b, c)  def partial(fn, *args):   print "args in partial : %s" %str(args)         def fn_part(*fn_args):     print "fn_args in fn_part : %s" %fn_args     return fn(*args+fn_args)       return fn_part  print_fn = partial(a_func, 'a', 'b')     print_fn('c') 

the output :

args in partial : ('a', 'b') fn_args in fn_part : c a: b: b c: c 

how control flow here ?

the function object print_fn points fn_part, has variables predefined (a , b). how can view variables defined function ?

the fn_part() function accesses args closure. read returned function object:

>>> print_fn = partial(a_func, 'a', 'b')     args in partial : ('a', 'b') >>> print_fn.__closure__ (<cell @ 0x102a90be8: tuple object @ 0x10075bf38>, <cell @ 0x102a901d8: function object @ 0x102aa1848>) >>> print_fn.__closure__[0].cell_contents ('a', 'b') 

you cannot alter closure; you'd create new partial() object instead, or call original function directly.