class_docstr: An HC class, inherited from Optimizer.
  
  This is the designed class to define HC-related
  variables and methods.
  
  References:
      S. Skiena. The Algorithm Design Manual (2010).
code: def r_mean(self, r_mean: float) -> None:
      if not isinstance(r_mean, (float, int)):
          raise e.TypeError("`r_mean` should be a float or integer")
  
      self._r_mean = r_mean
  
file_path: opytimizer/opytimizer/optimizers/misc/hc.py
imports: from typing import Any, Dict, Optional
  import opytimizer.math.random
  import opytimizer.utils.exception
  from opytimizer.core import Optimizer
  from opytimizer.core.space import Space
  from opytimizer.utils import logging
label_desc: Use image node_id 3 for calling the HC obj's underlying member method code with example usage: obj.r_mean(r_mean) without return types