content: from decimal import Decimal
  from django.utils.translation import gettext_lazy as _
  
  from .choices import WirelessChannelChoices
  
  __all__ = (
      'get_channel_attr',
  )
  
  
  def get_channel_attr(channel, attr):
      """
      Return the specified attribute of a given WirelessChannelChoices value.
      """
      if channel not in WirelessChannelChoices.values():
          raise ValueError(_("Invalid channel value: {channel}").format(channel=channel))
  
      channel_values = channel.split('-')
      attrs = {
          'band': channel_values[0],
          'id': int(channel_values[1]),
          'frequency': Decimal(channel_values[2]),
          'width': Decimal(channel_values[3]),
      }
      if attr not in attrs:
          raise ValueError(_("Invalid channel attribute: {name}").format(name=attr))
  
      return attrs[attr]
  