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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 _build_index():
 """ Rebuild _module_file_index from sys.modules """

    global _module_file_index
    _module_file_index = {
        mod.__file__: mod.__name__
        for mod in sys.modules.values()
        if hasattr(mod, '__file__') and hasattr(mod, '__name__')
    }