class_docstr: Hook to extend calls to MonitoredSession.run().
class_docstr_tok: ["Hook","to","extend","calls","to","MonitoredSession.run","(",")","."]
docstr: Called once before using the session.
  
  When called, the default graph is the one that will be launched in the
  session.  The hook can modify the graph by adding new operations to it.
  After the `begin()` call the graph will be finalized and the other callbacks
  can not modify the graph anymore. Second call of `begin()` on the same
  graph, should not change the graph.
docstr_tok: ["Called","once","before","using","the","session",".","When","called",",","the","default","graph","is","the","one","that","will","be","launched","in","the","session",".","The","hook","can","modify","the","graph","by","adding","new","operations","to","it",".","After","the","`","begin","(",")","`","call","the","graph","will","be","finalized","and","the","other","callbacks","can","not","modify","the","graph","anymore",".","Second","call","of","`","begin","(",")","`","on","the","same","graph",",","should","not","change","the","graph","."]
code: def begin(self):
      """Called once before using the session.
  
      When called, the default graph is the one that will be launched in the
      session.  The hook can modify the graph by adding new operations to it.
      After the `begin()` call the graph will be finalized and the other callbacks
      can not modify the graph anymore. Second call of `begin()` on the same
      graph, should not change the graph.
      """
      pass
  
file_path: tensorflow/tensorflow/python/training/session_run_hook.py
imports: import collections
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 1 for calling the SessionRunHook obj's underlying member method code with example usage: obj.begin() without return types