Text and Data Mining valid from 2019-11-08
Received: 29 May 2019
Accepted: 9 September 2019
First Online: 8 November 2019
Ethics approval and consent to participate
: The samples were collected in Rwanda in affiliation with University of Rwanda and the permission for research was received from the Ministry of Education of Rwanda.
: Not applicable
: We have no conflicts of interest to disclose.