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 = np.abs(args[1])
    p0i = param_estimator(x, y)
    silent = kw.pop('silent', True)
    if not silent:
        print('init guess: ', p0i)
    pars = S21p0i2params(x, p0i)
    # print 'init_guess', p0i
    fr = fit.fitxy(pars, y,  fn.S21_resonance_sloped, ret_fit=True)
    if not silent:
        fit.print_fitres(pars)
    fitpars = params2tuple(pars)
    fitparserr = paramserr2tuple(pars)
    output = {'fitpars': fitpars, 'parserr': fitparserr,
              'fit': fr[1], 'fitparsobj': pars, 'parsinit': p0i}
    return output
    # return pfit,errp,fr[1],fr[0],pars,p0i