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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def start(builtins=False, profile_threads=True):
 """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. """

    # 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)