code: def _validate(obj):
      cols = obj.columns
      if not all(vertex in cols for vertex in ["x", "y"]):
          raise AttributeError("Must have vertices 'x', 'y'.")
  
file_path: cudf/python/cudf/cudf/tests/test_custom_accessor.py
imports: import pandas
  import pytest
  import cudf
  from cudf.testing._utils import assert_eq
label_desc: Use image node_id 2 for calling the PointsAccessor obj's underlying member method code with example usage: obj._validate(obj) without return types