class_docstr: Higher-Order Factorization Machine base class.
class_docstr_tok: ["Higher-Order","Factorization","Machine","base","class","."]
code: def _interaction_combination_keys(self, x):
      for d in range(2, self.degree + 1):
          yield from itertools.combinations(x.keys(), d)
  
imports: from __future__ import annotations
  import collections
  import functools
  import itertools
  import numpy
  from river import base, optim, utils
  from .base import BaseFM
label_desc: Use image node_id 4 for calling the HOFM obj's underlying member method code with example usage: obj._interaction_combination_keys(x) without return types