code: def test_not_nparray():
      """If not an np.array, BadInputError raised"""
      with pytest.raises(error.BadInputError) as excinfo:
          some_fn([[np.nan, 2.0], [3, 4]])
      assert str(excinfo.value) == "Not a np.ndarray."
  
imports: import pytest
  import numpy
  from impyute.imputation.cs import mean
  from impyute.ops import error
  from impyute.ops import wrapper
label_desc: Use image node_id 8 for calling a global function with example usage: test_not_nparray() without return types