comparison operators – Is there an operation for not less than or not greater than in python?

Instead of a == 0 or a > 0 you could just use a >= 0.

Well python !> doesnt work.But

if not a > 70:

    print( The number is Not bigger than 70)

else:
    print( The number is DEFINITELY bigger than 70)

this surprisingly works

I was surprised to see that this particular operation does not exist in Python!

Im not familiar with any language that does have this operator. It is simply not needed.

As for your snippets:

if a == 0 or a > 0

It is exactly the same as if a >= 0