Given the following BL statements, draw the corresponding abstract syntax trees as defined by the mathematical model of StatementKernel. See Slides 5-12 in http://web.cse.ohio-state.edu/software/2231/web-sw2/extras/slides/21.Abstract-Syntax-Trees.pdf for some examples.

a. IF next-is-empty THEN move ELSE IF next-is-wall THEN turnright turnright move END IF END IF 

b. WHILE true DO turnright IF next-is-enemy THEN TurnAround ELSE skip END IF turnleft END WHILE