code: def detect_available_configs(interfaces=None):
      
  
      # Figure out where to search
      if interfaces is None:
          # use an iterator over the keys so we do not have to copy it
          interfaces = BACKENDS.keys()
      elif isinstance(interfaces, basestring):
          interfaces = [interfaces, ]
      # else it is supposed to be an iterable of strings
  
      result = []
      for interface in interfaces:
  
          try:
              bus_class = _get_class_for_interface(interface)
          except ImportError:
              log_autodetect.debug('interface "%s" can not be loaded for detection of available configurations', interface)
              continue
  
          # get available channels
          try:
              available = list(bus_class._detect_available_configs())
          except NotImplementedError:
              log_autodetect.debug('interface "%s" does not support detection of available configurations', interface)
          else:
              log_autodetect.debug('interface "%s" detected %i available configurations', interface, len(available))
  
              # add the interface name to the configs if it is not already present
              for config in available:
                  if 'interface' not in config:
                      config['interface'] = interface
  
              # append to result
              result += available
  
      return result
docs: Detect all configurations/channels that the interfaces could
      currently connect with.
  
      This might be quite time consuming.
  
      Automated configuration detection may not be implemented by
      every interface on every platform. This method will not raise
      an error in that case, but with rather return an empty list
      for that interface.
  
      :param interfaces: either
          - the name of an interface to be searched in as a string,
          - an iterable of interface names to search in, or
          - `None` to search in all known interfaces.
      :rtype: list[dict]
      :return: an iterable of dicts, each suitable for usage in
               the constructor of :class:`can.BusABC`.