problem with pickle

[K Gaur]

hello everybody
I've just started learning python . i stumbled upon this broad
spectrum function 'pickle'

but it is not getting executed as it should

this is what the python interpreter returns on giving the basic
command

>>>pickle.dump(x,f)         where x is a tuple and f is a file object

Traceback (most recent call last):
  File "<stdin>", line 1, in ?
NameError: name 'pickle' is not defined

kindly elucidate what's wrong

thanks