class_docstr: Alternative parameterization of Weibull Model
code: def _cumulative_hazard(self, params, T, Xs):
      exp_Xbeta = np.exp(np.dot(Xs["beta_"], params["beta_"]))
      lT = np.log(T)
      return exp_Xbeta * np.exp(params["phi1_"] * lT)
  
imports: from autograd import numpy
  from lifelines.datasets import load_lymph_node
  from lifelines.fitters import ParametricRegressionFitter
  from autograd.scipy.special import expit
  import pandas
  from lifelines import CoxPHFitter
  from matplotlib import pyplot
label_desc: Use image node_id 1 for calling the WeibullFitter obj's underlying member method code with example usage: obj._cumulative_hazard(params, T, Xs) and returns: unknown