def rvp_to_dbz(x):
    """Calculates dBZ-values from DWD RVP6 values as given in DX-product
    files.

    Parameters
    ----------
    x : int
        a number or an array

    Examples
    --------
    >>> from wradlib.trafo import rvp_to_dbz
    >>> print(rvp_to_dbz(65.))
    0.0
    """
    return x * 0.5 - 32.5