Return a dict (which I often call "response") with one or more of the

following as appropriate:



successful

This is a bool to indicate success.



pylons_response

If unsuccessful, this is a Pylons response object that your

controller can return. It will contain an appropriate error

message for the user.



file_handle

Upon success, this is the file handle returned by

``urllib2.urlopen``. Per urllib2, it has an ``info()`` method

containing things like headers, etc.



xml_document

Upon success, if you set ``parse_xml_document=True``, this will

contain the parsed xml_document. I'll take care of parsing errors

with an appropriate pylons_response for you.

server_response = talk_to_server(parse_xml_document=True)

if not server_response['successful']:

return server_response['pylons_response']

etag = server_response['file_handle'].info().getheader('ETag')

xml_document = server_response['xml_document']

If you are a strong believer in statically typed languages, you won't want to read this post!Sometimes it makes sense for a function to return multiple things. In such cases, it's common to just return them in a tuple: "return (count, new_obj)".Sometimes you might want to return objects of different types based on whether an operation succeeded or not. For instance, if the operation was successful, you might return "(True, obj)". If it failed, you might return "(False, reason)". Often, you can use exceptions to handle this situation.Sometimes you might want to return objects of different types based on arguments to the function. For instance, did the caller ask for the data in this format or that format?Sometimes you'll want all of these variations at the same time. In such cases, I have found that using a dict for your return value is a good solution. For instance, here is a piece of a docstring that I wrote yesterday:The calling code then looks like this:If you read it out loud, the code "reads" easily, and yet it has the flexibility to contain all the different things I need to return. If I ask for something that isn't there, I get an exception, which is life as usual for a Python programmer.