code: def _get_cov(r: Tensor, j: int, q: int) -> Tensor:
      if q == 0:
          return 1
      if q == 1:
          return (j + 1) * r + 1
      if q == 2:
          return 1 + (j + 2) * r + ((j + 4 * j + 3) / 3.0) * (r**2)
      if q == 3:
          return (
              1
              + (j + 3) * r
              + ((6 * j**2 + 36 * j + 45) / 15.0) * r.square()
              + ((j**3 + 9 * j**2 + 23 * j + 15) / 15.0) * (r**3)
          )
  
file_path: gpytorch/gpytorch/kernels/piecewise_polynomial_kernel.py
imports: import math
  from typing import Optional
  import torch
  from torch import Tensor
  from .kernel import Kernel
label_desc: Use image node_id 2 for calling a global function with example usage: _get_cov(r, j, q) and returns: int, unknown, unknown, unknown