def get(self, key):
self._create_file_if_none_exists()<EOL>with open(self.filename, '<STR_LIT:rb>') as file_object:<EOL><INDENT>cache_pickle = pickle.load(file_object)<EOL>val = cache_pickle.get(key, None)<EOL>return val<EOL><DEDENT>
Gets a value by a key.

        Args:
          key (str): Key to retrieve the value.

        Returns: Retrieved value.