class_docstr: Base class to build callbacks for :class:`~gensim.models.word2vec.Word2Vec` & subclasses.
  
  Callbacks are used to apply custom functions over the model at specific points
  during training (epoch start, batch end etc.). This is a base class and its purpose is to be inherited by
  custom Callbacks that implement one or more of its methods (depending on the point during training where they
  want some action to be taken).
  
  See examples at the module level docstring for how to define your own callbacks by inheriting  from this class.
  
  As of gensim 4.0.0, the following callbacks are no longer supported, and overriding them will have no effect:
  
  - on_batch_begin
  - on_batch_end
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docstr: Method called at the start of the training process.
  
  Parameters
  ----------
  model : :class:`~gensim.models.word2vec.Word2Vec` or subclass
      Current model.
docstr_tok: ["Method","called","at","the","start","of","the","training","process",".","Parameters","--","--","--","--","--","model",":",":","class",":","`","~gensim.models.word2vec.Word2Vec","`","or","subclass","Current","model","."]
code: def on_train_begin(self, model):
      """Method called at the start of the training process.
  
      Parameters
      ----------
      model : :class:`~gensim.models.word2vec.Word2Vec` or subclass
          Current model.
  
      """
      pass
  
imports: import gensim
  import logging
  import copy
  import sys
  import numpy
label_desc: Use image node_id 3 for calling the CallbackAny2Vec obj's underlying member method code with example usage: obj.on_train_begin(model) without return types