text: from __future__ import annotations
  
  from enum import Enum
  
  
  class ChannelType(Enum):
      BOOK = 0
      TRADE = 1
      TICKER = 2
      KLINE = 3
      BALANCE = 4
      ORDER = 5
  
      @classmethod
      def from_str(cls, s: str) -> ChannelType:
          return {t.name.lower(): t for t in cls}[s.lower()]
  