code: def var(expr, **kw):
      
  
      ddof = kw.get('ddof', kw.get('_ddof', 1))
  
      output_type = _stats_type(expr)
      return _reduction(expr, Var, output_type, _ddof=ddof)
docs: Variance
  
      :param expr:
      :param ddof: degree of freedom
      :param kw:
      :return: