**kwargs vs 10 arguments in a python function?

I am starting out with python and trying to construct an XML request for an ebay web service:

Now, my question is:

Say, this is my function:

def findBestMatchItemDetailsAcrossStores():
     request = """<?xml version="1.0" encoding="utf-8"?>
     <findBestMatchItemDetailsAcrossStoresRequest xmlns="http://www.ebay.com/marketplace/search/v1/services">
     <siteResultsPerPage>50</siteResultsPerPage>
     <entriesPerPage>50</entriesPerPage>
     <ignoreFeatured>true</ignoreFeatured>
     <keywords>ipod</keywords> <-----REQUIRED
     <itemFilter>
     <paramName>PriceMin</paramName>
     <paramValue>50</paramValue>
     <name>Currency</name>
     <value>USD</value>
     </itemFilter>
     <itemFilter>
     <paramName>PriceMax</paramName>
     <paramValue>100</paramValue>
     </itemFilter>
     </findBestMatchItemDetailsAcrossStoresRequest>"""
     return get_response(findBestMatchItemDetailsAcrossStores.__name__, request)

Where, keyword is the only required field. So, how should I construct the method? The ways can be:

1. Create an object, pass it to the func(object) : The java way
2. Pass all the arguments: func(a=val1, b=val2, c=val3, d=val4 etc)
3. Use **kwargs and trust the person who calls the function, that he 开发者_JAVA百科passes the right keys with the values, because I will use the keys to actually construct the XML tags.

Update:

All the xml tags you see in the request are needed to be passed by the user. But keywords should be passed and others maybe passed if required.

Any suggestions?

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A good idea is to put all the parameters with appropriate defaults (or just None defaults) in the function signature. Yeah, it will require a little more typing in the function itself, but the interface will be clean, self-documented and simple to use, as you won't have to look up possible parameters in ebay docs or function source. It will save you time later on.

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how about modeling the message as a class?

class FindBestMatchItemDetailsAcrossStoresRequest:
     def __init__(self,keywords):
         self.keywords = keywords # required parameters in the constructor
         # set up the default values....etc
         self.siteResultsPerPage = 50 
         self.name = 'Currency'


     def send(self):
         # build message from self.xxx
         return get_response()


 #usage
 req = FindBestMatchItemDetailsAcrossStoresRequest('ipod')
 response = req.send()

 #usage with optional args

 req.siteResultsPerPage = 150
 response = req.send()

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I would use named parameters for all. By doing this it is very easy to assign default values, and to force the user to supply required parameters (by omitting the default)