import torch


def mel_to_hz(mels: torch.Tensor):
    """
    Converts a Tensor of mel scaled frequencies to Hertz.
    Uses the simple formula by O'Shaughnessy (1987).

    Args:
        mels (torch.Tensor): mel frequencies to convert.
    """
    return 700 * (10**(mels / 2595) - 1)