docs: private Statement mergeStatements(Statement statement1, Statement statement2) {
  		if (!equivalentClaims(statement1.getClaim(), statement2.getClaim())) {
  			return null;
  		}
  
  		StatementRank newRank = statement1.getRank();
  		if (newRank == StatementRank.NORMAL) {
  			newRank = statement2.getRank();
  		} else if (statement2.getRank() != StatementRank.NORMAL
  				&& newRank != statement2.getRank()) {
  			return null;
  		}
  
  		String newStatementId = statement1.getStatementId();
  		if ("".equals(newStatementId)) {
  			newStatementId = statement2.getStatementId();
  		}
  
  		List<Reference> newReferences = mergeReferences(
  				statement1.getReferences(), statement2.getReferences());
  
  		return Datamodel.makeStatement(statement1.getClaim(), newReferences,
  				newRank, newStatementId);
  	}