Meaning
Defines a distinct type alias named Token based on bytes using typing.NewType for enhanced type safety.
Primary Function
Creates a new type that is distinct from plain bytes at static type-check time while retaining bytes at runtime.
Communicative Purpose
Signal that a value represents a token rather than generic bytes, preventing accidental mixing.
Pattern
NewType('<Name>', <base_type>)
Core Structure
NewType('Token', bytes)
Função primária
Creates a new type that is distinct from plain bytes at static type-check time while retaining bytes at runtime.
Propósito comunicativo
Signal that a value represents a token rather than generic bytes, preventing accidental mixing.
Situações de gatilho
When you need a token-like value (e.g., authentication token) that should not be confused with plain byte strings.
Contextos
Type annotations, function parameters, return types, variable declarations where a token is expected.
Padrão
NewType('<Name>', <base_type>)
Estrutura central
NewType('Token', bytes)
Slots de substituição
Token bytes
Colocados típicos
- NewType typing bytes Token type
Substituições comuns
- UserId = NewType('UserId'
- int) Token = NewType('Token'
- str)
Erros comuns
Confusing NewType with a simple alias (Token = bytes) Forgetting to import NewType from typing
Similar / contraste
Simple type alias: Token = bytes typing.NewType vs. typing.NewType
Interferências
Do not treat NewType as a runtime distinct type; it is only for static type checking.
Família do chunk
- typing.NewType
- type alias pattern
Nuance
At runtime, Token values are still bytes; the distinction exists only for static type checkers.
Efeito pragmático
Improves code clarity and prevents accidental misuse of byte values as tokens.
Dica de memória
Token = NewType('Token', bytes)
Upgrade path
Using NewType for other distinct types like UserId = NewType('UserId', int)
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