code: def test_check_column_single(dataframe):
      """
      Check works with a single input
      """
  
      assert check_column(dataframe, "a") is None
  
      with pytest.raises(ValueError):
          check_column(dataframe, "b")
  
      # should also work with non-string inputs
  
      with pytest.raises(ValueError):
          check_column(dataframe, 2)
  
      dataframe[2] = "asdf"
  
      assert check_column(dataframe, 2) is None
  
imports: import pytest
  from janitor.utils import check_column
label_desc: Use image node_id 2 for calling a global function with example usage: test_check_column_single(dataframe) without return types