Write a python function to set the left most unset bit.
def set_left_most_unset_bit(n): 
    if not (n & (n + 1)): 
        return n 
    pos, temp, count = 0, n, 0 
    while temp: 
        if not (temp & 1): 
            pos = count      
        count += 1; temp>>=1
    return (n | (1 << (pos))) 
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a python function to set the left most unset bit.
def set_left_most_unset_bit(n): 
    if not (n & (n + 1)): 
        return n 
    pos, temp, count = 0, n, 0 
    while temp: 
        if not (temp & 1): 
            pos = count      
        count += 1; temp>>=1
    return (n | (1 << (pos))) [/INST]assert set_left_most_unset_bit(10) == 14
assert set_left_most_unset_bit(12) == 14
assert set_left_most_unset_bit(15) == 15</s>