def getModel(self, modelIdentifier):
if modelIdentifier in self._models:<EOL><INDENT>return self._models[modelIdentifier]<EOL><DEDENT>else:<EOL><INDENT>message = "<STR_LIT>""<STR_LIT>".format(modelIdentifier)<EOL>raise Exception(message)<EOL><DEDENT>
Return the requested model.

:param modelIdentifier: <str> model identifier
:return: <object> model instance