code: def polynomial_kernel(
      X: ArrayLike,
      Y: Optional[ArrayLike] = None,
      degree: int = 3,
      gamma: Optional[float] = None,
      coef0: float = 1,
  ) -> ArrayLike:
      X, Y = check_pairwise_arrays(X, Y)
      if gamma is None:
          gamma = 1.0 / X.shape[1]
  
      K = (gamma * da.dot(X, Y.T) + coef0) ** degree
      return K
  
file_path: dask-ml/dask_ml/metrics/pairwise.py
imports: import warnings
  from typing import Any, Callable, Dict, Optional, Tuple, Union
  import dask.array
  import numpy
  from dask import delayed
  from dask.utils import derived_from
  from sklearn import metrics
  from sklearn.metrics.pairwise import KERNEL_PARAMS
  from .._typing import ArrayLike
  from ..utils import row_norms
label_desc: Use image node_id 7 for calling a global function with example usage: polynomial_kernel(X, Y, degree, gamma, coef0) and returns: K