Longest decreasing Subsequence

def LongestDecreasing(lista_in):
    lista_out = []
    c = 0
    for element in lista_in:
        if element < lista_out[-1]:
            lista_out.append(element)
        else:
            binarySearch(lista_out,element)
            lista_out[]




def binarySearch(alist, item):
    first = 0
    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(testlist, 21))