def binarysearch(alist, item):
    first
    last=len(alist)-1
    found=False

    while first <= last and not found:
          midpoint=(first + last)//2
          if alist[midpoint]==item:
             found==True
          else:
               if item < alist[midpoint]:
                  last = midpoint -1
               else:
                   first = midpoint +1
    return found
testlist = [0, 1, 2, 8, 13, 17, 19, 32, 42]
print (binarysearch (testlist,3))
print (binarysearch (testlich,13))
