How to use sadd with multiple elements in Redis using Python API?

When you see the syntax *values in an argument list, it means the function takes a variable number of arguments.

Therefore, call it as

r.sadd('a', 1, 2, 3)

You can pass an iterable by using the splat operator to unpack it:

r.sadd('a', *set([3, 4]))

or

r.sadd('a', *[3, 4])

Consider the following:

r.sadd('a', 1, 2, 3)

That should do the trick.