def __init__(self, import_name, exception):
        self.import_name = import_name
        self.exception = exception

        msg = (
            'import_string() failed for %r. Possible reasons are:\n\n'
            '- missing __init__.py in a package;\n'
            '- package or module path not included in sys.path;\n'
            '- duplicated package or module name taking precedence in '
            'sys.path;\n'
            '- missing module, class, function or variable;\n\n'
            'Debugged import:\n\n%s\n\n'
            'Original exception:\n\n%s: %s')

        name = ''
        tracked = []
        for part in import_name.replace(':', '.').split('.'):
            name += (name and '.') * part
            imported = import_string(name, silent=True)
            if imported:
                tracked.append((name, getattr(imported, '__file__', None)))
            else:
                track = ['- %r found in %r.' % (n, i) for n, i in tracked]
                track.append('- %r not found.' % name)
                msg = msg % (import_name, '\n'.join(track),
                             exception.__class__.__name__, str(exception))
                break

        ImportError.__init__(self, msg)
dataset/ETHPy150Open tony/tmuxp/tmuxp/testsuite/__init__.py/ImportStringError.__init__/operator `+` -> `*`