Binary search to find largest smaller element than given value python

import sys
def binary(s, num):
    l = len(s)
    mid = l/2
    #print "in binary s:" + str(s)
    #print "in binary num:" + str(num)
    #print "s[mid]:" + str(s[mid])
    if((l!=0) and  (l == 1)):
     if(s[mid] < num):
     return s[mid]
        #else:
#return None
    if((l!=0) and (l != 1)):
    if ((s[mid] >= num) and (s[mid - 1 ] < num)):
        return s[mid - 1]
    elif ((s[mid] > num) and (s[mid - 1] > num)):
        return binary(s[:mid -1] , num)
    else:
        return binary(s[mid:], num)


lst = [8,0]

print binary(sorted(lst), 4)

Output:

0

Sorting a list with out sort/sorted functions - Python

lst = [1,0,4,5,6,7,8,0,0,0]

print(lst)
cou = len(lst)
for i in range(cou):
    for j in range(1, cou-i):
       #descending
        """if lst[j] > lst[j-1]:
            (lst[j-1], lst[j]) = (lst[j], lst[j-1])"""
        #ascending  
        if lst[j] < lst[j-1]:
            (lst[j-1], lst[j]) = (lst[j], lst[j-1])
print(lst)