def __init__ ( self               ,
                   chain              ,   ## input TChain/TTree 
                   selection  = {}    ,   ## selection/cuts  
                   save_vars  = ()    ,   ## list of variables to save 
                   new_vars   = {}    ,   ## new variables
                   no_vars    = ()    ,   ## exclude these variables
                   ##
                   output     = ''    ,   ## output file name
                   name       = ''    ,   ## the name 
                   addselvars = False ,   ## add varibles from selections?
                   tmp_keep   = False ,   ## keep the temporary file 
                   silent     = False ):  ## silent processing