code: def start(builtins=False, profile_threads=True):
      
      # TODO: what about builtins False or profile_threads False?
      _vendorized_yappi.yappi.set_context_id_callback(
          lambda: greenlet and id(greenlet.getcurrent()) or 0)
  
      _vendorized_yappi.yappi.set_context_name_callback(
          lambda: greenlet and greenlet.getcurrent().__class__.__name__ or '')
  
      _vendorized_yappi.yappi.start(builtins, profile_threads)
docs: Starts profiling all threads and all greenlets.
  
      This function can be called from any thread at any time.
      Resumes profiling if stop() was called previously.
  
      * `builtins`: Profile builtin functions used by standart Python modules.
      * `profile_threads`: Profile all threads if ``True``, else profile only the
        calling thread.