Issue in pooling - custom connector!

Hello Friends

I am trying to build a polling mechanism for a trigger in a custom connector. The code shown in documentation is failing. Please see below:

poll: lambda do |connection, input, last_created_since|

page_size = 100

created_since = (last_created_since || input['created_since'] || input['since'])

customers = get("https://api.stripe.com/v1/customers") . 

params(created_since: created_since.iso8601,

order: 'asc',

limit: 100)['customers'] || []

Now the entire set of params is throwing error - saying created_since, order & limit are not valid.

Any suggestions on this? 

Thanks in anticipation,

Angshu