def binary_search(item_list,item):  
    first = 0  
    last = len(item_list)-1  
    found = False  
    while( first<=last and not found):  
        mid = (first + last)//2  
        if item_list[mid] == item :  
            found = True  
        else:  
            if item < item_list[mid]:  
                last = mid - 1  
            else:  
                first = mid + 1   
    return found  
      
print(binary_search([1,2,3,5,8], 6))  
print(binary_search([1,2,3,5,8], 5))