<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def import_json(cls, filename):
 """ Import graph from the given file. The file is expected to contain UTF-8 encoded JSON data. """

        with open(filename, 'rb') as f:
            json_graph = f.read().decode('utf-8')
        return cls.from_json(json_graph)