```
def show_volume(name=None, kwargs=None, instance_id=None, call=None):
    '''
    Show volume details
    '''
    if not kwargs:
        kwargs = {}

    if 'volume_id' not in kwargs:
        log.error('A volume_id is required.')
        return False

    params = {'Action': 'DescribeVolumes',
              'VolumeId.1': kwargs['volume_id']}

    data = query(params, return_root=True)
    return data
```
 `name` and  `instance_id` - were unused arguments, removed them. Author probably planned to extend that function in future.
`kwargs` and `call` - were the only used arguments - left them