code: protected static StatementGroup findStatementGroup(PropertyIdValue pid,
  			StatementDocument document) {
  		for (StatementGroup sg : document.getStatementGroups()) {
  			if (pid.equals(sg.getProperty())) {
  				return sg;
  			}
  		}
  		return null;
  	}
docs: Finds the {@link StatementGroup} for the given property in a document.
  
  @param pid
  the property to look for
  @param document
  the document to search
  @return the {@link StatementGroup} with this property, or null if there
  is none