code: private Extensions getOrCreate(String mappingTable) {
  
  		getOrCreate();
  
  		Extensions extension = getOrCreate(EXTENSION_NAME, mappingTable, null,
  				EXTENSION_DEFINITION, ExtensionScopeType.READ_WRITE);
  
  		return extension;
  	}
docs: Get or create the extension
  
  @param mappingTable
  mapping table name
  @return extension