SingleHistogramDefinition Node1 SingleHistogramDefinition + nBinsX + nBinsY + nBinsZ + xAxis + yAxis + zAxis + m_empty + SingleHistogramDefinition() + SingleHistogramDefinition() + SingleHistogramDefinition() + SingleHistogramDefinition() + empty() + str() + validType() + isValid() + stringIndex() + titleDigest() + stringIndex() Node2 std::string Node2->Node1 +name +folder +title +histoType +allTitles +zTitle +yTitle +xTitle Node3 std::basic_string< char > Node3->Node2