def unstandardize(data, mus_sigs):
    """
    Applies the inverse transformation to return to original data.

    Args
    ----
      data: pandas DataFrame with zero mean and std of one.
      mus_sigs: tuple where first value is the mean used for the standardization and
                second value is the respective standard deviaion.

    Returns
    -------
      data: pandas DataFrame with mean and std given by input ``mus_sigs``
    """
    mu, sig = mus_sigs
    data = data * sig + mu
    return data
