How is the uniqueness of elements ensured when using a set data structure?

In Python, the set data structure ensures the uniqueness of elements by using a hash table. Each element must be hashable (immutable and have a hash method). When adding an element, its hash is computed, and if an element with the same hash and equality (eq) already exists in the set, the new element is not added.

Example:

s = set()
s.add(1)
s.add(2)
s.add(1)  # will not be added, as 1 already exists
print(s)  # output: {1, 2}

Thus, uniqueness is achieved through hashing and equality checks of elements.