src/Baum/SetValidator.php
protected function validateDuplicates() {
    return (
      !$this->duplicatesExistForColumn($this->node->getQualifiedLeftColumnName()) &&
      !$this->duplicatesExistForColumn($this->node->getQualifiedRightColumnName())
    );
  }
protected function validateDuplicates() {
    return (
      !$this->duplicatesExistForColumn($this->node->getQualifiedLeftColumnName()) &&
      !$this->duplicatesExistForColumn($this->node->getQualifiedRightColumnName())
    );
  }
Checks that there are no duplicates for the `lft` and `rgt` columns.

@return boolean