The typing.NamedTuple class syntax only looks at the namespace's __annotations__ when creating a named tuple, which means that any attribute without a type annotation is not considered to be a field: ...

from collections import namedtuple s = namedtuple('Result', 'a one_over_a')(5, 1 / float(5)) s. # <-- I DO see a and one_over_a in the list. Upon typing the period, a ...