How to use proxies with pytrends

[info3g]

Hi,
In pytrends there is a proxies parameter in which we can pass list of proxies, I have bought some paid proxies but my program goes into exception. It gives following output

proxy Error. Changing IP
proxy Error. Changing IP
proxy Error. Changing IP
proxy Error. Changing IP

I want to know does the proxy parameter works and if it does from where should I buy proxies to make it work?

Also does the proxy list works in parallel manner or in series manner?
parallel: if I make 10 requests and i have 5 proxies in a list does each proxy take 2 request and returns the result?
series: if I make 10 requests and i have 5 proxies in a list do all the requests are made through first proxy till it gets blocked and then the next proxy will make the remaining requests?