class_docstr: An ISA class, inherited from Optimizer.
  
  This is the designed class to define ISA-related
  variables and methods.
  
  References:
      A. Mortazavi, V. Toğan and A. Nuhoğlu.
      Interactive search algorithm: A new hybrid metaheuristic optimization algorithm.
      Engineering Applications of Artificial Intelligence (2018).
docstr: Array of velocities.
docstr_tok: ["Array","of","velocities","."]
code: def velocity(self) -> np.ndarray:
      """Array of velocities."""
  
      return self._velocity
  
imports: import copy
  import time
  from typing import Any, Dict, Optional
  import numpy
  import opytimizer.math.random
  import opytimizer.utils.constant
  import opytimizer.utils.exception
  from opytimizer.core import Optimizer
  from opytimizer.core.function import Function
  from opytimizer.core.space import Space
  from opytimizer.utils import logging
label_desc: Use image node_id 8 for calling the ISA obj's underlying member method code with example usage: obj.velocity() and returns: self