def setUpTestData(cls):
        batch_num = 0
        section_num = 0
        voter_num = 0
        party_num = 0
        position_num = 0
        candidate_num = 0
        num_elections = 2
        voters = list()
        positions = dict()
        for i in range(num_elections):
            election = Election.objects.create(name='Election {}'.format(i))
            positions[str(election.name)] = list()

            num_batches = 2
            for j in range(num_batches):
                batch = Batch.objects.create(year=batch_num, election=election)
                batch_num += 1

                num_sections = 2 if j == 0 else 1
                for k in range(num_sections):
                    section = Section.objects.create(
                        section_name=str(section_num)
                    )
                    section_num += 1

                    num_students = 2
                    for l in range(num_students):
                        voter = User.objects.create(
                            username='user{}'.format(voter_num),
                            first_name=str(voter_num),
                            last_name=str(voter_num),
                            type=UserType.VOTER
                        )
                        voter.set_password('voter')
                        voter.save()
                        voter_num += 1

                        VoterProfile.objects.create(
                            user=voter,
                            batch=batch,
                            section=section
                        )

                        voters.append(voter)

            num_positions = 3
            for i in range(num_positions):
                position = CandidatePosition.objects.create(
                    position_name='Position {}'.format(position_num),
                    election=election
                )

                positions[str(election.name)].append(position)

                position_num += 1

            num_parties = 3
            for j in range(num_parties):
                party = CandidateParty.objects.create(
                    party_name='Party {}'.format(party_num),
                    election=election
                )
                party_num += 1

                if j != 2:  # Let every third party have no candidates.
                    num_positions = 3
                    for k in range(num_positions):
                        position = positions[str(election.name)][k]

                        candidate = Candidate.objects.create(
                            user=voters[candidate_num],
                            party=party,
                            position=position,
                            election=election
                        )

                        Vote.objects.create(
                            user=voters[candidate_num],
                            candidate=candidate,
                            election=election
                        )

                        candidate_num += 1

        # Let's give one candidate an additional vote to really make sure that
        # we all got the correct number of votes.
        Vote.objects.create(
            user=voters[0],
            # NOTE: The voter in voter[1] is a Position 1 candidate of
            #       Party 1, where the voter in voter[0] is a member.
            candidate=Candidate.objects.get(user=voters[1]),
            election=Election.objects.get(name='Election 0')
        )

        _admin = User.objects.create(username='admin', type=UserType.ADMIN)
        _admin.set_password('root')
        _admin.save()
def subset_examples(example_dict, indices_to_keep, create_new_dict=False):
    """Subsets examples in dictionary.

    :param example_dict: See doc for `write_example_file`.
    :param indices_to_keep: 1-D numpy array with indices of examples to keep.
    :param create_new_dict: Boolean flag.  If True, this method will create a
        new dictionary, leaving the input dictionary untouched.
    :return: example_dict: Same as input, but possibly with fewer examples.
    """

    error_checking.assert_is_integer_numpy_array(indices_to_keep)
    error_checking.assert_is_numpy_array(indices_to_keep, num_dimensions=1)
    error_checking.assert_is_boolean(create_new_dict)

    if not create_new_dict:
        for this_key in MAIN_KEYS:
            optional_key_missing = (
                this_key not in REQUIRED_MAIN_KEYS
                and this_key not in example_dict
            )

            if optional_key_missing:
                continue

            if this_key == TARGET_MATRIX_KEY:
                if this_key in example_dict:
                    example_dict[this_key] = (
                        example_dict[this_key][indices_to_keep, ...]
                    )
                else:
                    example_dict[TARGET_VALUES_KEY] = (
                        example_dict[TARGET_VALUES_KEY][indices_to_keep]
                    )

                continue

            if this_key == FULL_IDS_KEY:
                example_dict[this_key] = [
                    example_dict[this_key][k] for k in indices_to_keep
                ]
            else:
                example_dict[this_key] = example_dict[this_key][
                    indices_to_keep, ...]

        return example_dict

    new_example_dict = {}

    for this_key in METADATA_KEYS:
        sounding_key_missing = (
            this_key in [SOUNDING_FIELDS_KEY, SOUNDING_HEIGHTS_KEY]
            and this_key not in example_dict
        )

        if sounding_key_missing:
            continue

        if this_key == TARGET_NAMES_KEY:
            if this_key in example_dict:
                new_example_dict[this_key] = example_dict[this_key]
            else:
                new_example_dict[TARGET_NAME_KEY] = example_dict[
                    TARGET_NAME_KEY]

            continue

        new_example_dict[this_key] = example_dict[this_key]

    for this_key in MAIN_KEYS:
        optional_key_missing = (
            this_key not in REQUIRED_MAIN_KEYS
            and this_key not in example_dict
        )

        if optional_key_missing:
            continue

        if this_key == TARGET_MATRIX_KEY:
            if this_key in example_dict:
                new_example_dict[this_key] = (
                    example_dict[this_key][indices_to_keep, ...]
                )
            else:
                new_example_dict[TARGET_VALUES_KEY] = (
                    example_dict[TARGET_VALUES_KEY][indices_to_keep]
                )

            continue

        if this_key == FULL_IDS_KEY:
            new_example_dict[this_key] = [
                example_dict[this_key][k] for k in indices_to_keep
            ]
        else:
            new_example_dict[this_key] = example_dict[this_key][
                indices_to_keep, ...]

    return new_example_dict