Added tests for the non default parameters of the sum_series function and removed related print statements because print statements are not a great way to test code.
Added tests for the non default parameters of the sum_series function and removed related print statements because print statements are not a great way to test code.

Baumelbi/IntroPython2016,UWPCE-PythonCert/IntroPython2016,UWPCE-PythonCert/IntroPython2016,Baumelbi/IntroPython2016,weidnem/IntroPython2016,UWPCE-PythonCert/IntroPython2016,weidnem/IntroPython2016,weidnem/IntroPython2016