def METHOD_NAME(*args, **kw):
    '''
    input:
    x,y
    returns fitresults with:
    fr[0]=(A,f0,Q,s21min,slope,theta)
    '''
    # print 'no slope'
    if type(args[0]) == Data:
        dat = args[0]
        xy = dat.get_data()
        x = xy[:, 0]
        y = xy[:, 1]
    else:
        x = args[0]
        y = args[1]
    silent = kw.pop('silent', True)
    p0i = param_estimator_complex(x, y)
    if not silent:
        print('init guess: ', p0i)
    pars = S21p0i2paramsc(x, p0i)
    fr = fit.fitxy(pars, y, fn.disp_hanger_S21_complex_sloped, ret_fit=True)
    if not silent:
        fit.print_fitres(pars)
    fitpars = params2tuple(pars)
    fitparserr = paramserr2tuple(pars)
    output = {'fitpars': fitpars, 'fitparserr': fitparserr,
              'fit': fr[1], 'fitparsobj': pars, 'parsinit': p0i}
    return output
    # return pfit,errp,fr[1],fr[0],pars,p0i