class_docstr: A WDO class, inherited from Optimizer.
  
  This is the designed class to define WDO-related
  variables and methods.
  
  References:
      Z. Bayraktar et al. The wind driven optimization technique and its application in electromagnetics.
      IEEE transactions on antennas and propagation (2013).
docstr: Array of velocities.
docstr_tok: ["Array","of","velocities","."]
code: def velocity(self) -> np.ndarray:
      """Array of velocities."""
  
      return self._velocity
  
imports: from typing import Any, Dict, Optional
  import numpy
  import opytimizer.math.random
  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 12 for calling the WDO obj's underlying member method code with example usage: obj.velocity() and returns: self