class_docstr: class for two sample comparison
  
  The tests and the confidence interval work for multi-endpoint comparison:
  If d1 and d2 have the same number of rows, then each column of the data
  in d1 is compared with the corresponding column in d2.
  
  Parameters
  ----------
  d1, d2 : instances of DescrStatsW
  
  Notes
  -----
  The result for the statistical tests and the confidence interval are
  independent of the user specified ddof.
  
  TODO: Extend to any number of groups or write a version that works in that
  case, like in SAS and SPSS.
docstr: assume d1, d2 hold the relevant attributes
  
          
docstr_tok: ["assume","d1",",","d2","hold","the","relevant","attributes"]
code: def __init__(self, d1, d2):
      """assume d1, d2 hold the relevant attributes"""
      self.d1 = d1
      self.d2 = d2
  
imports: import numpy
  from scipy import stats
  from statsmodels.tools.decorators import cache_readonly
label_desc: Use image node_id 1 to create a new CompareMeans object  with example: obj = CompareMeans(d1, d2)