code: def read_vensim(mdl_file):
      
  
      from .py_backend.vensim.vensim2py import translate_vensim
      from .py_backend import functions
      py_model_file = translate_vensim(mdl_file)
      model = functions.Model(py_model_file)
      model.mdl_file = mdl_file
      return model
docs: Construct a model from Vensim `.mdl` file.
  
      Parameters
      ----------
      mdl_file : <string>
          The relative path filename for a raw Vensim `.mdl` file
  
      Returns
      -------
      model: a PySD class object
          Elements from the python model are loaded into the PySD class and ready to run
  
      Examples
      --------
      >>> model = read_vensim('../tests/test-models/samples/teacup/teacup.mdl')