def var(series):
    """
    Returns the variance of values in a series.

    Args:
        series (pandas.Series): column to summarize.
    """
    if np.issubdtype(series.dtype, np.number):
        return series.var()
    else:
        return np.nan
Returns the variance of values in a series.

    Args:
        series (pandas.Series): column to summarize.