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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 DeleteUser(username):
 """Deletes a GRR user from the datastore."""

  grr_api = maintenance_utils.InitGRRRootAPI()
  try:
    grr_api.GrrUser(username).Get().Delete()
  except api_errors.ResourceNotFoundError:
    raise UserNotFoundError(username)