Experience accessing USGS EST services using python?

I am writing python code that will be passed gage ID(s) and then generate a REST specific URL to access the instantaneous parameter values I am querying. I am new to Python, but have got the code working up to the generation of the URL.

I am using the package 'urllib' to access the URL. But, and here is where it gets foggy, I am assuming that I need to save the response (in WaterML format) to digest later in the code (using the ElementTree XML API). If this is true, please correct if not, how do I go about it?