Wah How to use Whether or not.

When we are not sure or we don't care which one is true, we can use Whether or not. 

• I’m not sure whether I can park here or not. (I am not sure that I can park here or I cannot park here.)

And we can say like this:

• I’m not sure whether or not I can park here. 

When we use the word whether, we imply that there will be two things to choose. If the other thing is or not, then you can leave it off, as in:

• I’m not sure whether I can park here. (Because we already know that "or not" means I cannot park here.)

Let's see other examples:

• I don't care whether you come or not. (It does not matter to me whether or not you come.)
• I don't care whether you go or not. (It's all the same to me whether you go or stay.)
• I don't know whether or not I am ready for this surgery. 
• I'm not sure whether or not I locked the door.
• You can come to the baseball game whether you have enough money or not.

I am not sure whether it is a lion or not.