Need to write teast cases in sinon to validate recurly API for project in React.

I am currently working on a project in React. It follows Test Driven Development. I write the test cases in sinon to validate everything. I am working on a file that has third party API called recurly. I create recurly client, get subscriptions and return the valid data. I have an issue in the test cases that i wrote and it is not able to recognize the .each() function in the file. Can anyone help me to get my testcases to pass.