docstr: a value error should be raised if method=quantile and num_buckets is not provided
code: def test_quantile_requires_num_buckets(self):
      """a value error should be raised if method=quantile and num_buckets is not provided"""
  
      selected_method = "quantile"
      with pytest.raises(
          ValueError,
          match=f"{selected_method} method expects num_buckets",
      ):
          Discretiser(method=selected_method)
  
imports: import math
  import numpy
  import pytest
  from causalnex.discretiser import Discretiser
label_desc: Use image node_id 3 for calling the TestErrorHandling obj's underlying member method code with example usage: obj.test_quantile_requires_num_buckets() without return types