generators that defer to sub-generators
<p>I yould like to have generators that defer to other generators, e.g.</p>

<pre><code>def gx():
    for i in [1, 2, 3]:
        yield i

def gy():
    for i in [11, 12, 13]:
        yield i

def gz():
    """this should defer to gx and gy to
       generate [1, 2, 3, 11, 12, 13]"""
    for i in gx(): yield i
    for i in gy(): yield i
</code></pre>

<p>Is the explicit loop in gz() the only way to do this, or are there better alternatives?</p>
