code: def set_prior_probs(self, statements):
          
          self.scorer.check_prior_probs(statements)
          for st in statements:
              st.belief = self.scorer.score_statement(st)
docs: Sets the prior belief probabilities for a list of INDRA Statements.
  
          The Statements are assumed to be de-duplicated. In other words,
          each Statement in the list passed to this function is assumed to have
          a list of Evidence objects that support it. The prior probability of
          each Statement is calculated based on the number of Evidences it has
          and their sources.
  
          Parameters
          ----------
          statements : list[indra.statements.Statement]
              A list of INDRA Statements whose belief scores are to
              be calculated. Each Statement object's belief attribute is updated
              by this function.