docstr: Required dimensionality of input to this function.
code: def required_dimensionality(self) -> Optional[int]:
      """Required dimensionality of input to this function."""
      return self._required_dimensionality
  
imports: from abc import ABC, abstractmethod
  from typing import Any, Callable, List, Optional, Tuple, Union
  import numpy
  import torch
  from ax.utils.common.docutils import copy_doc
  from ax.utils.common.typeutils import checked_cast, not_none
  from botorch.test_functions import synthetic
label_desc: Use image node_id 4 for calling the SyntheticFunction obj's underlying member method code with example usage: obj.required_dimensionality() and returns: self