class_docstr: Results class for treatment effect estimation
  
  Parameters
  ----------
  teff : instance of TreatmentEffect class
  results_gmm : instance of GMMResults class
  method : string
      Method and estimator of treatment effect.
  kwds: dict
      Other keywords with additional information.
  
  Notes
  -----
  This class is a subclass of ContrastResults and inherits methods like
  summary, summary_frame and conf_int. Attributes correspond to a z-test
  given by ``GMMResults.t_test``.
class_docstr_tok: ["Results","class","for","treatment","effect","estimation","Parameters","--","--","--","--","--","teff",":","instance","of","TreatmentEffect","class","results_gmm",":","instance","of","GMMResults","class","method",":","string","Method","and","estimator","of","treatment","effect",".","kwds",":","dict","Other","keywords","with","additional","information",".","Notes","--","--","-","This","class","is","a","subclass","of","ContrastResults","and","inherits","methods","like","summary",",","summary_frame","and","conf_int",".","Attributes","correspond","to","a","z-test","given","by","``","GMMResults.t_test","``","."]
code: def __init__(self, teff, results_gmm, method, **kwds):
      super().__init__()
      k_params = len(results_gmm.params)
      constraints = np.zeros((3, k_params))
      constraints[0, 0] = 1
      constraints[1, 1] = 1
      constraints[2, :2] = [1, 1]
      tt = results_gmm.t_test(constraints)
      self.__dict__.update(tt.__dict__)
      self.teff = teff
      self.results_gmm = results_gmm
      self.method = method
      # TODO: make those explicit?
      self.__dict__.update(kwds)
  
      self.c_names = ["ATE", "POM0", "POM1"]
  
imports: import numpy
  from statsmodels.compat.pandas import Substitution
  from scipy.linalg import block_diag
  from statsmodels.regression.linear_model import WLS
  from statsmodels.sandbox.regression.gmm import GMM
  from statsmodels.stats.contrast import ContrastResults
  from statsmodels.tools.docstring import indent
label_desc: Use image node_id 1 to create a new TreatmentEffectResults object from inherited base classes: ContrastResults with example: obj = TreatmentEffectResults(teff, results_gmm, method)