code: def get_source_model_lt(oqparam, validate=True):
      
      fname = oqparam.inputs.get('source_model_logic_tree')
      if fname:
          # NB: converting the random_seed into an integer is needed on Windows
          return logictree.SourceModelLogicTree(
              fname, validate, seed=int(oqparam.random_seed),
              num_samples=oqparam.number_of_logic_tree_samples)
      return logictree.FakeSmlt(oqparam.inputs['source_model'],
                                int(oqparam.random_seed),
                                oqparam.number_of_logic_tree_samples)
docs: :param oqparam:
          an :class:`openquake.commonlib.oqvalidation.OqParam` instance
      :returns:
          a :class:`openquake.commonlib.logictree.SourceModelLogicTree`
          instance