code: def load_json_model(filename):
      
      if isinstance(filename, string_types):
          with open(filename, "r") as file_handle:
              return model_from_dict(json.load(file_handle))
      else:
          return model_from_dict(json.load(filename))
docs: Load a cobra model from a file in JSON format.
  
      Parameters
      ----------
      filename : str or file-like
          File path or descriptor that contains the JSON document describing the
          cobra model.
  
      Returns
      -------
      cobra.Model
          The cobra model as represented in the JSON document.
  
      See Also
      --------
      from_json : Load from a string.