class_docstr: Wraps multiple callbacks in an ready-to-use class.
docstr: Performs a list of callbacks prior to the `update` method.
docstr_tok: ["Performs","a","list","of","callbacks","prior","to","the","`","update","`","method","."]
code: def on_update_before(self, *update_args) -> None:
      """Performs a list of callbacks prior to the `update` method."""
  
      for callback in self.callbacks:
          callback.on_update_before(*update_args)
  
imports: from typing import List, TypeVar, Union
  import numpy
  import opytimizer.utils.exception
  from opytimizer.core.space import Space
label_desc: Use image node_id 10 for calling the CallbackVessel obj's underlying member method code with example usage: obj.on_update_before() without return types