RDFSharp.Query.RDFAskQuery.AddPatternGroup C# (CSharp) Method

        public RDFAskQuery AddPatternGroup(RDFPatternGroup patternGroup)
        {
            if (patternGroup != null) {
                if (!this.PatternGroups.Exists(pg => pg.PatternGroupName.Equals(patternGroup.PatternGroupName, StringComparison.Ordinal))) {
                     this.PatternGroups.Add(patternGroup);
                }
            }
            return this;
        }