fs_leer = frozenset()
print(fs_leer)
fs_voll = frozenset({1, 2, 3, 4})
print(fs_voll)

print()
fs = frozenset([1, 2, 3, 4])
print(fs)
#fs = frozenset([[1, 2], [3, 4]])       # TypeError: unhashable type: 'list'

print()
d = {frozenset({1, 2, 3, 4}) : "Hello World"}
print(d)
print(type(d))

#d = {{1, 2, 3, 4} : "Hello World"}     # TypeError: unhashable type: 'set'