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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def assist(self, project_path, source, position, filename):
 """Return completion match and list of completion proposals :param project_path: absolute project path :param source: unicode or byte string code source :param position: character or byte cursor position :param filename: absolute path of file with source code :returns: tuple (completion match, sorted list of proposals) """

        return self._call('assist', project_path, source, position, filename)