18th November 2021

Coding⚑

Python⚑

Type Hints⚑

• New: Define a TypeVar with restrictions.

  from typing import TypeVar
  
  AnyStr = TypeVar('AnyStr', str, bytes)
  

• New: Use a constrained TypeVar in the definition of a class attributes.

  If you try to use a TypeVar in the definition of a class attribute:

  class File:
      """Model a computer file."""
  
      path: str
      content: Optional[AnyStr] = None # mypy error!
  

  mypy will complain with Type variable AnyStr is unbound [valid-type], to solve it, you need to make the class inherit from the Generic[AnyStr].

  class File(Generic[AnyStr]):
      """Model a computer file."""
  
      path: str
      content: Optional[AnyStr] = None
  

Properties⚑

• New: Give an overview on Python's @property decorator.

Pydantic⚑

• New: Define fields to exclude from exporting at config level.

  Eagerly waiting for the release of the version 1.9 because you can define the fields to exclude in the Config of the model using something like:

  class User(BaseModel):
      id: int
      username: str
      password: str
  
  class Transaction(BaseModel):
      id: str
      user: User
      value: int
  
      class Config:
          fields = {
              'value': {
                  'alias': 'Amount',
                  'exclude': ...,
              },
              'user': {
                  'exclude': {'username', 'password'}
              },
              'id': {
                  'dump_alias': 'external_id'
              }
          }
  

  The release it's taking its time because the developer's gremlin and salaried work are sucking his time off.

Operative Systems⚑

Linux⚑

Vim⚑

• Correction: Correct vim snippet to remember the folds when saving a file.