code: def p_elseif_elseiflist(p):
      
      label_, cond_ = p[1]
      then_ = p[2]
      else_ = p[3]
      p[0] = make_block(label_, make_sentence('IF', cond_, then_, else_, lineno=p.lineno(1)))
docs: elseiflist : elseif_expr program_co elseiflist