class_docstr: This class tests for different I/O feature data types for an .mlmodel
  It will cover the following areas to test for:
  - All features must have a valid type
  - Multiarrays must have a valid dataType. Inputs must specify shape. Shape must have >= 0 elements
  - Images must have a valid colorspace. width & height have to be >= 0
  - Dictionaries must have a valid key type
code: def scikit_data(self):
      return load_boston()
  
imports: import unittest
  import numpy
  import PIL.Image
  import coremltools
  from coremltools._deps import _HAS_SKLEARN, MSG_SKLEARN_NOT_FOUND
  from coremltools.models.utils import _is_macos, _macos_version
label_desc: Use image node_id 1 for calling the TestIODataTypes obj's underlying member method code with example usage: obj.scikit_data() and returns: load_boston