code: public AbstractPrintQuery addAttribute(final Attribute... _attributes)
      {
          if (isMarked4execute()) {
              for (final Attribute attr : _attributes) {
                  final OneSelect oneselect = new OneSelect(this, attr);
                  this.allSelects.add(oneselect);
                  this.attr2OneSelect.put(attr.getName(), oneselect);
              }
          }
          return this;
      }
docs: Add an attribute to the PrintQuery. It is used to get editable values
  from the eFaps DataBase.
  
  @param _attributes Attribute to add
  @return this PrintQuery