class_docstr: Test statistic holder for Wald-type tests
  
  Parameters
  ----------
  stat : float
      The test statistic
  df : int
      Degree of freedom.
  null : str
      A statement of the test's null hypothesis
  alternative : str
      A statement of the test's alternative hypothesis
  name : str, default "" (empty)
      Name of test
code: def __str__(self) -> str:
      name = "" if not self._name else self._name + "\n"
      msg = (
          "{name}H0: {null}\n{name}H1: {alternative}\nStatistic: {stat:0.4f}\n"
          "P-value: {pval:0.4f}\nDistributed: {dist}"
      )
      return msg.format(
          name=name,
          null=self.null,
          alternative=self.alternative,
          stat=self.stat,
          pval=self.pval,
          dist=self.dist_name,
      )
  
file_path: arch/arch/utility/testing.py
imports: from __future__ import annotations
  from functools import cached_property
  from scipy.stats import chi2
label_desc: Use image node_id 7 for calling the WaldTestStatistic obj's underlying member method code with example usage: obj.__str__() and returns: msg