code: func FromContext(ctx context.Context) Logger {
  	if ctx == nil {
  		return NopLogger
  	}
  	l, ok := ctx.Value(logKey).(Logger)
  	if !ok {
  		return NopLogger
  	}
  	return l
  }
docs: // FromContext gets the logger out of the context.
  // If not logger is stored in the context, a NopLogger is returned.