Source code for 1_integer_sum
"""
Sum of Integers Up To n
========================
Write a function, ``add_it_up()``, that takes a single positive
integer as input and returns the sum of the integers from zero
to the input parameter included.
The function should return 0 if a non-integer is passed in.
"""
[docs]def add_it_up(integer: int) -> int:
"""
Sum all the integers from ``0`` to ``integer``.
``integer`` must be a positive integer number, otherwise ``0``
is returned.
:param integer: positive integer number.
:type integer: int
:return: sum of all positive integers up to ``integer`` included;
``0`` if ``integer`` is not a positive integer.
"""
if isinstance(integer, int) and integer >= 0:
return sum(range(integer + 1))
else:
return 0
if __name__ == '__main__':
assert add_it_up(0) == 0
assert add_it_up(1) == 1
assert add_it_up(5.6) == 0
assert add_it_up(-5) == 0
assert add_it_up(100) == 5050