text: __all__ = ('SystemChannelFlag',)
  
  from ..bases import ReverseFlagBase
  
  class SystemChannelFlag(ReverseFlagBase):
      """
      The flags of a ``Guild``'s system channel.
      
      For Discord these flags tell, what ``MessageType`-s are not sent to the guild's system channel, but the wrapper
      reverses this behaviour.
      
      The implemented system channel flags are the following:
      
      +---------------------------+-------------------+
      | Respective name           | Bitwise position  |
      +===========================+===================+
      | welcome                   | 0                 |
      +---------------------------+-------------------+
      | boost                     | 1                 |
      +---------------------------+-------------------+
      | setup_tips                | 2                 |
      +---------------------------+-------------------+
      
      There are also predefined ``SystemChannelFlag``-s:
      
      +-----------------------+-----------------------+
      | Class attribute name  | value                 |
      +=======================+=======================+
      | NONE                  | ActivityFlag(0b111)   |
      +-----------------------+-----------------------+
      | ALL                   | ActivityFlag(0b000)   |
      +-----------------------+-----------------------+
      """
      __keys__ = {
          'welcome': 0,
          'boost': 1,
          'setup_tips': 2,
      }
      
      @property
      def none(self):
          """
          Whether the flag not allows any system messages at the respective system channel.
          
          Returns
          -------
          none : `bool`
          """
          return (self == self.NONE)
      
      @property
      def all(self):
          """
          Whether the flag allows all the system messages at the respective system channel.
          
          Returns
          -------
          none : `bool`
          """
          return (self == self.ALL)
      
      NONE = NotImplemented
      ALL = NotImplemented
  
  SystemChannelFlag.NONE = SystemChannelFlag(0b111)
  SystemChannelFlag.ALL = SystemChannelFlag(0b000)
  