Python，PEP-8和多行字典格式化

Question

我必須在Python中聲明一些dict。我寫這樣的代碼：

class MegaClass(object): 
    _activation_grad_classes = \ 
    { 
     activation.ForwardStrictRELU: activation.BackwardStrictRELU, 
     activation.ForwardLog: activation.BackwardLog, 
     activation.ForwardSinCos: activation.BackwardSinCos 
    } 

並得到一個PEP-8錯誤：E122 continuation line missing indentation or outdented。

我該如何解決？

Answer 1

把大括號的賦值行：

_activation_grad_classes = { 
    activation.ForwardStrictRELU: activation.BackwardStrictRELU, 
    activation.ForwardLog: activation.BackwardLog, 
    activation.ForwardSinCos: activation.BackwardSinCos 
} 

有很少是需要使用\逃脫Python中的換行;改爲使用{..},[..]和(..)跨多行對錶達式分組。