betty.factory module

Functionality for creating new class instances.

class betty.factory.Factory

Bases: Protocol

A callable to create a new instance.

__init__(*args, **kwargs)

exception betty.factory.FactoryError

Bases: RuntimeError

Raised when a class could not be instantiated by a factory API.

classmethod new(new_cls: type) → Self

Create a new instance.

class betty.factory.IndependentFactory

Bases: ABC

Provide a factory for classes that can instantiate themselves asynchronously.

abstract async classmethod new() → Self

Create a new instance.

exception betty.factory.InitFactoryError

Bases: FactoryError

Raised when a class could not be instantiated by calling it directly.

classmethod new(new_cls: type) → Self

Create a new instance.

class betty.factory.TargetFactory

Bases: ABC

Provide a factory for classes that depend on self.

abstract async new_target(cls: type[_T]) → _T

Create a new instance.

Raises:

FactoryError – raised when cls could not be instantiated.

async betty.factory.new(cls: type[_T]) → _T

Create a new instance.

Returns:

1. If cls extends betty.factory.IndependentFactory, this will call return cls’s

   new()’s return value.

2. Otherwise cls() will be called without arguments, and the resulting instance will be returned.

Raises:

FactoryError – raised when cls could not be instantiated.