code: def oblique_variants(
      oblique_mercator,
      rotated_mercator,
  ) -> Tuple[
      ccrs.ObliqueMercator, ccrs.ObliqueMercator, ccrs.ObliqueMercator
  ]:
      """Setup three ObliqueMercator objects, two identical, for eq testing."""
      default = oblique_mercator
      alt_1 = rotated_mercator
      alt_2 = deepcopy(rotated_mercator)
      return default, alt_1, alt_2
  
file_path: cartopy/lib/cartopy/tests/crs/test_oblique_mercator.py
imports: from copy import deepcopy
  from typing import Dict, List, NamedTuple, Tuple
  import numpy
  import pytest
  import cartopy.crs
  from .helpers import check_proj_params
label_desc: Use image node_id 4 for calling a global function with example usage: oblique_variants(oblique_mercator, rotated_mercator) and returns: default,  alt_1,  alt_2