class_docstr: Factorization machine base class.
class_docstr_tok: ["Factorization","machine","base","class","."]
code: def _interaction_names(self, x):
      return [
          f"{j1} - {j2}"
          for j1, j2 in itertools.combinations(x.keys(), 2)
      ]
  
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 3 for calling the FM obj's underlying member method code with example usage: obj._interaction_names(x) and returns: unknown