import torch


def _calculate_accuracy(output: torch.Tensor, actual_labels: torch.Tensor) -> float:
    """Calculates accuracy of multiclass prediction.

    Args:
        output (torch.Tensor): Output predictions from neural network.
        actual_labels (torch.Tensor): Actual labels.
    """
    predicted_labels = torch.argmax(output, dim=1)
    num_correct = (predicted_labels == actual_labels).sum()
    num_train = len(actual_labels)
    accuracy = (float(num_correct) / float(num_train)) * 100
    return accuracy