code: public File getParentDirectory() {
          if (this.parentDirectory == null) {
              // the conventions are:
              // 1. jar in the function's method folder or
              // 2. in the function method's parent folder where all the method directories are children
  
              if (isJarInMethodFolder()) { 
                  this.parentDirectory = getJarDirectory().getAbsoluteFile().getParentFile(); //up one level
              }
              this.parentDirectory = this.jarDirectory.getAbsoluteFile(); // otherwise convention #2
          }
          return this.parentDirectory;
      }
docs: Gets the function method's parent directory where each function method should be residing (1-level up)