old_contents: 
  import os
  import json
  from ._config import VIS3D_OPTION_FILE, VIS3D_METHOD_FILE, VIS3D_DATASET_FILE, \
                      API_DIR
  
  
  def load_resource(src):
      _dir = os.path.dirname(__file__)
      object_builder_file = os.path.join(_dir, API_DIR, src)
      with open(object_builder_file) as obj_build:
          return json.load(obj_build)
  
  
  class State(object):
      """
      Contains all 'ezvis3d' API, options and methods
      """
  
      def __init__(self):
          self._OPTION = load_resource(VIS3D_OPTION_FILE)
          self._METHOD = load_resource(VIS3D_METHOD_FILE)
          self._DATASET = load_resource(VIS3D_DATASET_FILE)
  
  state_VIS3D = State()
  
  
new_contents: 
  import os
  import json
  from ._config import VIS3D_OPTION_FILE, VIS3D_METHOD_FILE, VIS3D_DATASET_FILE, \
                      API_DIR
  
  
  def load_resource(src):
      _dir = os.path.dirname(__file__)
      object_builder_file = os.path.join(_dir, API_DIR, src)
      with open(object_builder_file, encoding='UTF-8') as obj_build:
          return json.load(obj_build)
  
  
  class State(object):
      """
      Contains all 'ezvis3d' API, options and methods
      """
  
      def __init__(self):
          self._OPTION = load_resource(VIS3D_OPTION_FILE)
          self._METHOD = load_resource(VIS3D_METHOD_FILE)
          self._DATASET = load_resource(VIS3D_DATASET_FILE)
  
  state_VIS3D = State()
  
  
subject: correct file encoding (for windows)