Fix Python – How to calculate rolling / moving average using python + NumPy / SciPy?

There seems to be no function that simply calculates the moving average on numpy/scipy, leading to convoluted solutions.
My question is two-fold:

What’s the easiest way to (correctly) implement a moving average with numpy?
Since this seems non-trivial and error prone, is there a good reason not to have the batteries included in this case?