gets a list of all the packages that were affected by ``operation``, splits it up (there can be multiple packages on a line), and then
    flattens that list. We make it to a list for easier parsing.

def _output_format(out,
                   operation):
    '''
    gets a list of all the packages that were affected by ``operation``, splits it up (there can be multiple packages on a line), and then
    flattens that list. We make it to a list for easier parsing.
    '''
    return [s.split()[1:] for s in out
            if s.startswith(operation)]