code: def _get_converter(self, convert_to=None):
          '''see convert and save. This is a helper function that returns 
             the proper conversion function, but doesn't call it. We do this
             so that in the case of convert, we do the conversion and return
             a string. In the case of save, we save the recipe to file for the 
             user.
  
             Parameters
             ==========
             convert_to: a string either docker or singularity, if a different
  
             Returns
             =======
             converter: the function to do the conversion
  
          '''
          conversion = self._get_conversion_type(convert_to)
  
          # Perform conversion
          if conversion == "singularity":
              return self.docker2singularity
          return self.singularity2dockef _get_converter(self, convert_to=None):
          '''see convert and save. This is a helper function that returns 
             the proper conversion function, but doesn't call it. We do this
             so that in the case of convert, we do the conversion and return
             a string. In the case of save, we save the recipe to file for the 
             user.
  
             Parameters
             ==========
             convert_to: a string either docker or singularity, if a different
  
             Returns
             =======
             converter: the function to do the conversion
  
          '''
          conversion = self._get_conversion_type(convert_to)
  
          # Perform conversion
          if conversion == "singularity":
              return self.docker2singularity
          return self.singularity2docker
docs: see convert and save. This is a helper function that returns 
             the proper conversion function, but doesn't call it. We do this
             so that in the case of convert, we do the conversion and return
             a string. In the case of save, we save the recipe to file for the 
             user.
  
             Parameters
             ==========
             convert_to: a string either docker or singularity, if a different
  
             Returns
             =======
             converter: the function to do the conversion