code: def _validate_num_channels(input_filepath_list, combine_type):
      ''' Check if files in input file list have the same number of channels
      '''
      channels = [
          file_info.channels(f) for f in input_filepath_list
      ]
      if not core.all_equal(channels):
          raise IOError(
              "Input files do not have the same number of channels. The "
              "{} combine type requires that all files have the same "
              "number of channels"
              .format(combine_type)
          f _validate_num_channels(input_filepath_list, combine_type):
      ''' Check if files in input file list have the same number of channels
      '''
      channels = [
          file_info.channels(f) for f in input_filepath_list
      ]
      if not core.all_equal(channels):
          raise IOError(
              "Input files do not have the same number of channels. The "
              "{} combine type requires that all files have the same "
              "number of channels"
              .format(combine_type)
          )
docs: Check if files in input file list have the same number of channels