docs: def get_input_channel(entity):
      """Similar to :meth:`get_input_peer`, but for :tl:`InputChannel`'s alone."""
      try:
          if entity.SUBCLASS_OF_ID == 0x40f202fd:  # crc32(b'InputChannel')
              return entity
      except AttributeError:
          _raise_cast_fail(entity, 'InputChannel')
  
      if isinstance(entity, (types.Channel, types.ChannelForbidden)):
          return types.InputChannel(entity.id, entity.access_hash or 0)
  
      if isinstance(entity, types.InputPeerChannel):
          return types.InputChannel(entity.channel_id, entity.access_hash)
  
      _raise_cast_fail(entity, 'InputChannel')