Received: 9 August 2019
Accepted: 10 February 2020
First Online: 9 April 2020
Ethics approval and consent to participate
: Written consent was obtained from each participant and ethical approval for the research was obtained from Addis Ababa University, College of natural and computational sciences, Institutional review board committee (IRB number: IRB/032/2018).
: Not applicable.
: The authors declare that they have no competing interests.