Do a function over a list of columns and return the result
    Parameters:
    df - DataFrame
        DataFrame to operate on
    col_list - list of strings
        names of columns to coerce
    func - function
        function to use

def cols_(df,col_list,func,*args,**kwargs):
    """ Do a function over a list of columns and return the result
    Parameters:
    df - DataFrame
        DataFrame to operate on
    col_list - list of strings
        names of columns to coerce
    func - function
        function to use
    """
    return _pd.DataFrame({col_name:func(df,col_name,*args,**kwargs) for col_name in col_list})