docstr: Implementation of the synthetic function. Must be implemented in subclass.
  
  Args:
      X (numpy.ndarray): an n by d array, where n represents the number
          of observations and d is the dimensionality of the inputs.
  
  Returns:
      numpy.ndarray: an n-dimensional array.
code: def _f(self, X: np.ndarray) -> float:
      """Implementation of the synthetic function. Must be implemented in subclass.
  
      Args:
          X (numpy.ndarray): an n by d array, where n represents the number
              of observations and d is the dimensionality of the inputs.
  
      Returns:
          numpy.ndarray: an n-dimensional array.
      """
      ...
  
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 10 for calling the SyntheticFunction obj's underlying member method code with example usage: obj._f(X) without return types