code: def test_element_not_present():
      elements = get_elements(n=10)
      dis = DisjointSet(elements)
  
      with assert_raises(KeyError):
          dis["dummy"]
  
      with assert_raises(KeyError):
          dis.merge(elements[0], "dummy")
  
      with assert_raises(KeyError):
          dis.connected(elements[0], "dummy")
  
file_path: catboost/contrib/python/scipy/py3/scipy/cluster/tests/test_disjoint_set.py
imports: import pytest
  from pytest import raises
  import numpy
  from scipy.cluster.hierarchy import DisjointSet
  import string
label_desc: Use image node_id 7 for calling a global function with example usage: test_element_not_present() without return types