from warnings import warn


def pc2in(picas):
    """
    Converts picas to inches

    Parameters
    ----------
    picas : int or float
        dimension in picas

    Returns
    -------
    inches : float
        dimensions in inches
    """
    if picas not in [19, 27, 33, 39, 68]:
        warn("Not a standard AMS width")
    return picas / 6.