'Returns the group with the specified id.
Arguments:
group_id (int): ID of the partition group.
Raises:
NoSuchUserPartitionGroupError: The specified group could not be found.'

def get_group(self, group_id):

    for group in self.groups:
        if (group.id == group_id):
            return group
    raise NoSuchUserPartitionGroupError('Could    not    find    a    Group    with    ID    [{group_id}]    in    UserPartition    [{partition_id}].'.format(group_id=group_id, partition_id=self.id))
