class_docstr: A Node instance is used for composing tree-based structures.
class_docstr_tok: ["A","Node","instance","is","used","for","composing","tree-based","structures","."]
docstr: Category of the node.
docstr_tok: ["Category","of","the","node","."]
code: def category(self) -> str:
      """Category of the node."""
  
      return self._category
  
imports: from __future__ import annotations
  from typing import Any, Dict, List, Optional, Union
  import numpy
  import opytimizer.utils.constant
  import opytimizer.utils.exception
label_desc: Use image node_id 6 for calling the Node obj's underlying member method code with example usage: obj.category() and returns: self