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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 StartFlowAndWait(client_id, token=None, timeout=DEFAULT_TIMEOUT, **flow_args):
 """Runs a flow and waits for it to finish. Args: client_id: The client id of the client to run on. token: The datastore access token. timeout: How long to wait for a flow to complete, maximum. **flow_args: Pass through to flow. Returns: The urn of the flow that was run. """

  flow_urn = flow.StartAFF4Flow(
      client_id=client_id, token=token, sync=True, **flow_args)

  WaitForFlow(flow_urn, token=token, timeout=timeout)

  return flow_urn