code: public function removeFields($fieldNames, FormMapper $formMapper)
      {
          if (!is_array($fieldNames)) {
              $fieldNames = array($fieldNames);
          }
  
          foreach ($fieldNames as $fieldName) {
              $formMapper->remove($fieldName);
          }
  
          $this->removeEmptyGroups();
  
          return $this;
      }
docs: Removes field (and also removes the tab when the tab/group is empty)
  
  @param string|array $fieldNames one fieldname or array of fieldnames
  @param FormMapper $formMapper
  @return self