def _forward_one_ovo(clf_idx, multi_ovo, test_x, verbose):
    """Perform forward on an OVO classifier.

    Parameters
    ----------
    clf_idx : int
        Index of the OVO classifier.
    multi_ovo : CClassifierMulticlassOVO
        Instance of the multiclass OVO classifier.
    test_x : CArray
        Test data as 2D CArray.
    verbose : int
        Verbosity level of the logger.

    """
    # Resetting verbosity level. This is needed as objects
    # change id  when passed to subprocesses and our logging
    # level is stored per-object looking to id
    multi_ovo.verbose = verbose

    multi_ovo.logger.info(
        "Forward for classes: {:}".format(multi_ovo._clf_pair_idx[clf_idx]))

    # Perform forward on data for current class classifier
    return multi_ovo._binary_classifiers[clf_idx].forward(test_x)