Implementing code review comment for https://github.com/Microsoft/pxt/pull/785
Implementing code review comment for https://github.com/Microsoft/pxt/pull/785

Microsoft/pxt,switchinnovations/pxt,playi/pxt,switchinnovations/pxt,switch-education/pxt,Microsoft/pxt,switch-education/pxt,switchinnovations/pxt,playi/pxt,playi/pxt,Microsoft/pxt,Microsoft/pxt,switch-education/pxt,switchinnovations/pxt,Microsoft/pxt,playi/pxt,switch-education/pxt,switch-education/pxt