Hello

Take a look on this example, it should help you.

Product.template -> product.product (one2many) -> product.attribute.value (many2many)

models = xmlrpclib.ServerProxy('{}/xmlrpc/2/object'.format(url))
prods = models.execute_kw(
            db, uid, password,
            'product.template', 'search_read',
            [[['categ_id', '=', 6]]],
            dict(fields=['name', 'product_variant_ids'], limit=7)
)
for prod in prods:
    print "%(name)s [%(id)s] - %%d variants  " % prod % len(prod.get('product_variant_ids'))
    variants = models.execute_kw(
                db, uid, password,
                'product.product', 'read',
                [prod.get('product_variant_ids')],
                dict(fields=['name', 'lst_price', 'attribute_value_ids'])
    )
    for variant in variants:
        print "\t %(name)s - %(lst_price)s" % variant
        atts = models.execute_kw(
                db, uid, password,
                'product.attribute.value', 'read',
                [variant.get('attribute_value_ids')],
                dict(fields=['name', 'attribute_id', 'price_extra'])
        )
        for att in atts:
            print "\t\t %%s: %(name)s (+ %(price_extra)s) " % att % att.get('attribute_id')[1]

Output from runbot 131156-9-0-ee42be.runbot9.odoo.com:

Apple In-Ear Headphones [10] - 1 variants  
	 Apple In-Ear Headphones - 79.0
Apple Wireless Keyboard [12] - 1 variants  
	 Apple Wireless Keyboard - 47.0
Bose Mini Bluetooth Speaker [7] - 1 variants  
	 Bose Mini Bluetooth Speaker - 247.0
iMac [11] - 1 variants  
	 iMac - 1799.0
iPod [14] - 2 variants  
	 iPod - 16.5
		 Memory: 16 GB (+ 0.0) 
	 iPod - 22.9
		 Memory: 32 GB (+ 0.0) 
iPad Mini [9] - 1 variants  
	 iPad Mini - 320.0
iPad Retina Display [6] - 3 variants  
	 iPad Retina Display - 750.0
		 Memory: 16 GB (+ 0.0) 
		 Color: White (+ 0.0) 
		 Wi-Fi: 2.4 GHz (+ 0.0) 
	 iPad Retina Display - 750.0
		 Memory: 16 GB (+ 0.0) 
		 Color: Black (+ 0.0) 
		 Wi-Fi: 2.4 GHz (+ 0.0) 
	 iPad Retina Display - 800.4
		 Memory: 32 GB (+ 0.0) 
		 Color: White (+ 0.0) 
		 Wi-Fi: 2.4 GHz (+ 0.0) 
30m RJ45 wire [55] - 1 variants  
	 30m RJ45 wire - 250.0