1.
Don’t Rely On Discipline
Neyts Zupan — @nzupan
https://paretosecurity.com

2.
@nzupan

3.
@nzupan

4.
Types are the “unit-tests” of
the coming decade
@nzupan

5.
class Person:
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan
https://github.com/zupo/discipline

6.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
@nzupan

7.
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
@nzupan

8.
class Person:
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
@nzupan

9.
class Person:
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
@nzupan

10.
class Person:
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
@nzupan

11.
class Person:
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
>>> han.grandparents
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/zupo/work/discipline/step1.py", line 13, in grandparents
grandparents.append(self.mother.mother)
AttributeError: 'NoneType' object has no attribute 'mother'
@nzupan

12.
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

13.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

14.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

15.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
$ mypy step2.py
step2.py:21: error: Item "None" of "Optional[Person]" has no attribute "mother"
step2.py:22: error: Item "None" of "Optional[Person]" has no attribute "father"
step2.py:23: error: Item "None" of "Optional[Person]" has no attribute "mother"
step2.py:24: error: Item "None" of "Optional[Person]" has no attribute "father"
Found 4 errors in 1 file (checked 1 source file)
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person):
grandparents = []
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

16.
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person):
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents

17.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person):
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

18.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person):
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

19.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person):
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

20.
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents

21.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

22.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
@nzupan

23.
$ mypy step4.py
step4.py:26: error: Incompatible return value type (got “List[Optional[Person]]", expected
"List[Person]")
Found 1 error in 1 file (checked 1 source file)
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return grandparents
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []

24.
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return [
person
for person in grandparents
if person is not None
]

25.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []
assert kylo.grandparents == [padme, anakin]
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return [
person
for person in grandparents
if person is not None
]
@nzupan

26.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []
assert kylo.grandparents == [padme, anakin]
def test_json():
assert (
json.dumps(han.json) ==
'{"name": "Han Solo", "mother": null, "father": null}'
)
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def json(self) -> t.Dict[str, t.Optional[str]]:
return {
"name": self.name,
"mother": self.mother.name if self.mother else None,
"father": self.father.name if self.father else None,
}
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return [
person
for person in grandparents
if person is not None
]

27.
jobal = Person("Jobal Naberrie")
ruwee = Person("Ruwee Naberrie")
padme = Person("Padme Amidala", mother=jobal, father=ruwee)
shmi = Person("Shmi Skywalker Lars")
force = Person("The Force")
anakin = Person("Anakin Skywalker", mother=shmi, father=force)
luke = Person("Luke Skywalker", mother=padme, father=anakin)
leia = Person("Leia Organa", mother=padme, father=anakin)
han = Person("Han Solo")
kylo = Person("Kylo Ren", mother=leia, father=han)
def test_person():
foo = Person("foo")
assert f"{foo}" == "foo"
assert foo.name == "foo"
def test_grandparents():
assert luke.grandparents == [jobal, ruwee, shmi, force]
assert han.grandparents == []
assert kylo.grandparents == [padme, anakin]
def test_json():
assert (
json.dumps(han.json) ==
'{"name": "Han Solo", "mother": null, "father": null}'
)
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(self, name, mother=None, father=None):
self.name = name
self.mother = mother
self.father = father
def __repr__(self):
return self.name
@property
def json(self) -> t.Dict[str, t.Optional[str]]:
return {
"name": self.name,
"mother": self.mother.name if self.mother else None,
"father": self.father.name if self.father else None,
}
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return [
person
for person in grandparents
if person is not None
]

28.
from __future__ import annotations
import json
import typing as t
class Person:
mother: t.Optional[Person]
father: t.Optional[Person]
def __init__(
self,
name: str,
mother: t.Optional[Person] = None,
father: t.Optional[Person] = None,
) -> None:
self.name = name
self.mother = mother
self.father = father
def __repr__(self: Person) -> str:
return self.name
@property
def json(self: Person) -> t.Dict[str, t.Optional[str]]:
return {
"name": self.name,
"mother": self.mother.name if self.mother else None,
"father": self.father.name if self.father else None,
}
@property
def grandparents(self: Person) -> t.List[Person]:
grandparents = []
if self.mother:
grandparents.append(self.mother.mother)
grandparents.append(self.mother.father)
if self.father:
grandparents.append(self.father.mother)
grandparents.append(self.father.father)
return [
person for person in grandparents
if person is not None
]
@nzupan

29.
@nzupan

30.
Documentation is bad, m’kay
@nzupan

31.
@nzupan

32.
@nzupan

33.
@nzupan

34.
@nzupan

35.
@nzupan

36.
@nzupan

37.
-Oh no … Homebrew does not have this lib
that I need, now what :(
-Gawd, need to install 15 system-wide C-based
dependencies just to try this Python graphing
lib
-What is this “libfoo” doing in my /var/lib, is it
a leftover from an ancient project and can be
removed?
-“Works on my machine” ¯_(ツ)_/¯
-New contractor needs help setting up their
local dev env … there goes my day :(

38.
-Every ~3 months nuke my Python from orbit:
-strange Homebrew / pyenv permission
errors
-strange bugs or failing tests
-completely broken side project

39.
@nzupan
https://niteo.co/blog/project-
isolation-beyond-requirements-txt

40.
@nzupan

41.
@nzupan

42.
“PYCONIT” for 30% o
f
https://paretosecurity.com

43.
https://github.com/pylons/
pyramid_openapi3

44.
@nzupan

45.
@nzupan

46.
Neyts Zupan — @nzupan
https://paretosecurity.com
Something needs documenting?
Write code instead!