def to_model
      mv = @value ? @value.to_model : nil
      met = @effective_time ? @effective_time.to_model : nil
      mtr = @temporal_references
      mso = @subset_operators
      HQMF::DataCriteria.new(@id, @title, nil, @description, @code_list_id, @children_criteria,
                             @derivation_operator, @definition, @status, mv, field_values, met, @inline_code_list,
                             @negation, @negation_code_list_id, mtr, mso, @specific_occurrence,
                             @specific_occurrence_const, @source_data_criteria, @comments, @variable)
    end
def to_model
      mv = @value ? @value.to_model : nil
      met = @effective_time ? @effective_time.to_model : nil
      mtr = @temporal_references
      mso = @subset_operators
      HQMF::DataCriteria.new(@id, @title, nil, @description, @code_list_id, @children_criteria,
                             @derivation_operator, @definition, @status, mv, field_values, met, @inline_code_list,
                             @negation, @negation_code_list_id, mtr, mso, @specific_occurrence,
                             @specific_occurrence_const, @source_data_criteria, @comments, @variable)
    end
Generates this classes hqmf-model equivalent