docstr: Two polygons are equal if they contain each other.
docstr_tok: ["Two","polygons","are","equal","if","they","contain","each","other","."]
code: def _preprocess(self, lhs, rhs):
      """Two polygons are equal if they contain each other."""
      lhs_contains_rhs = lhs.contains(rhs)
      rhs_contains_lhs = rhs.contains(lhs)
      return lhs_contains_rhs & rhs_contains_lhs
  
imports: from __future__ import annotations
  from typing import Generic, TypeVar
  import cupy
  import cudf
  from cudf import Series
  import cuspatial
  from cuspatial.core.binpreds.binpred_interface import BinPred, EqualsOpResult, ImpossiblePredicate, NotImplementedPredicate, PreprocessorResult
  from cuspatial.utils.binpred_utils import LineString, MultiPoint, Point, Polygon, _false_series
label_desc: Use image node_id 1 for calling the PolygonPolygonEquals obj's underlying member method code with example usage: obj._preprocess(lhs, rhs) and returns: unknown