How to program for binary search in python

How to program for binary search in python.

1. def binary_search(search,lst):
    flag=0
    start=0
    end=len(lst)-1
    while start<=end :
    mid = (start + end) // 2
    if lst[mid] < search:
    start=mid+1
    elif lst[mid]>search:
    end=mid-1
    else:
    flag=1
    break
    if flag==0:
    print("not found.")
    else:
    print("Found.")
   elements=[]
   num_of_elmenets=int(input("how many elment you want to Enter: "))
   for i in range(num_of_elmenets):
    elm=int(input("Enter element "))
    elements.append(elm)
   elements.sort()
   ser=int(input("enter the value to search: "))
   
   
   binary_search(ser,elements)
2. 
   

Output:-