pschanely

def make_bigger(n: int) -> int:
  '''
  post: __return__ != 100
  '''
  return 2 * n + 10

pschanely

class HasConsistentHash:
    '''
    A mixin to enforce that classes have hash methods that are consistent
    with thier equality checks.
    '''
    def __eq__(self, other: object) -> bool:
        '''
        post: implies(__return__, hash(self) == hash(other))
        '''
        raise NotImplementedError

pschanely

class HasConsistentHash:
    '''
    A mixin to enforce that classes have hash methods that are consistent
    with thier equality checks.
    '''
    def __eq__(self, other: object) -> bool:
        '''
        post: implies(__return__, hash(self) == hash(other))
        '''
        raise NotImplementedError

pschanely

from typing import List

def average(numbers: List[float]) -> float:
    '''
    pre: len(numbers) >= 0
    post: min(numbers) <= __return__ <= max(numbers)
    '''
    return sum(numbers) / len(numbers)

pschanely

from typing import List

def csv_last_column(lines: List[str]) -> List[str]:
    '''
    Gets you the last column from a csv.
    We use CrossHair to confirm our index arithmetic is correct.
    
    pre: all(',' in line for line in lines)
    post: __return__ == [line.split(',')[-1] for line in lines]
    '''

pschanely

import dataclasses
from typing import List

@dataclasses.dataclass
class AverageableStack:
    '''
    A stack of numbers with a O(1) average() operation.
    inv: self._total == sum(self._values)
    '''
    _values: List[int]

pschanely

import dataclasses
from typing import List

@dataclasses.dataclass
class AverageableQueue:
    '''
    A queue of numbers with a O(1) average() operation.
    inv: self._total == sum(self._values)
    '''
    _values: List[int]

pschanely

def make_bigger(n: int) -> int:
  '''
  post: __return__ != 0
  '''
  return 2 * n + 10

pschanely

from typing import Final

class Cat:
    legs: Final[int] = 4

def walk(cat: Cat, strides: int) -> int:
    '''
    pre: strides > 0
    post: __return__ >= 4
    '''

pschanely

from typing import TypedDict

class Movie(TypedDict):
    name: str
    year: int

def age(movie: Movie) -> int:
    '''
    pre: move.age < 2020
    post: __return__ >= 0