code: public static void clearEvidence(ProbabilisticNetwork bn, String nodeName)
              throws ShanksException {
          ProbabilisticNode node = (ProbabilisticNode) bn.getNode(nodeName);
          ShanksAgentBayesianReasoningCapability.clearEvidence(bn, node);
      }
docs: Clear a hard evidence fixed in a given node
  
  /**
  
  @param bn
  @param nodeName
  @throws ShanksException