import argparse
from ROOT import TFile, RooWorkspace

def main():

    parser = argparse.ArgumentParser()
    parser.add_argument( '-f', '--file' )
    parser.add_argument( '-p', '--params' )
    args = parser.parse_args()

    tfile = TFile( args.file )
    w = tfile.Get( 'w' )

    params = args.params.split( ',' )

    for param in params:

        param_var = w.obj( param )
        try:
            param_val = param_var.getValV()
            param_err = param_var.getError()
            print( "{} = {} +/- {}".format( param, round( param_val, 2 ), round( param_err, 2 ) ) )
        except:
            print( "Something went wrong, maybe the parameter doesn't exist in this workspace" )    

if __name__ == '__main__':
    main()