Python interpreter session playing around with coroutines

coroutines.py

>>> def gen():
...     while True:
...             x = (yield)
...             print(x)
... 
>>> a = gen()
>>> a.send('hi')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: can't send non-None value to a just-started generator
>>> 
>>> def consumer(func):
...     def wrapper(*args, **kw):
...             f = func(*args, **kw)
...             next(f)
...             return f
...     return wrapper
... 
>>> @consumer
... def another_gen():
...     while True:
...             x = (yield)
...             print(x)
... 
>>> b = another_gen()
>>> b.send('hi')
hi

# 
# the consumer decorator primes the coroutine
#